Packaging for transporting and / or storing radioactive materials, comprising a simplified radiological protection device, reducing the risks of radiological leaks

Abstract

The invention relates to a packaging (1) for transporting and / or storing radioactive materials, comprising a body delimiting a cavity (12) for housing the radioactive materials (3), the packaging comprising at least one radiological protection enclosure (14, 14a, 24) formed by enclosure wall elements (30, 32), each enclosure delimiting with its elements (30, 32) one single space (26) in which is arranged a radiological protection device (28) comprising a plurality of prefabricated blocks (30a, 30b) that follow one another along a given direction (13), in such a way as to face one another. At least several blocks are each held on at least one of the elements (30, 32) by at least one holding member (36a, 36b) cooperating with said block and with said at least one of the associated enclosure wall elements.

Description

[0001] DESCRIPTION

[0002] TITLE: PACKAGING FOR THE TRANSPORT AND / OR STORAGE OF RADIOACTIVE MATERIALS, INCLUDING A SIMPLIFIED RADIOLOGICAL PROTECTION DEVICE, REDUCING THE RISKS OF RADIOLOGICAL LEAKS

[0003] TECHNICAL FIELD

[0004] The present invention relates to the field of packaging for transporting and / or storing radioactive materials, for example nuclear fuel assemblies or radioactive waste.

[0005] More specifically, the invention relates to a package comprising a radiological protection device formed by a plurality of prefabricated blocks.

[0006] STATE OF THE PRIOR ART

[0007] From the prior art, it is known to provide a package provided with one or more radiological protection devices arranged around a cavity housing the radioactive materials, or in the closing lid of this package. The function sought with this device lies in protection against gamma radiation, and / or in neutron absorption in order to comply with the regulatory radiological criteria around the package, when it is loaded with radioactive materials. To do this, one solution consists of inserting radiological protection elements into an enclosure, for example an enclosure delimiting an annular space centered on the longitudinal central axis of the package, around the cavity housing the radioactive materials. These radiological protection elements usually take the form of prefabricated blocks, which, thanks to cold play, can be introduced into this space.This cold clearance also allows thermal expansion of the radiological protection material, and thus limits the thermomechanical constraints of these blocks on the parts of the packaging which define the space concerned.

[0008] During transport operations carried out with this type of packaging, as well as during their handling, the radiological protection blocks can move and slide relative to each other in the dedicated space. The cumulative movements between these blocks can locally lead, between two adjacent blocks, to the appearance of a clearance of an unacceptable value with regard to radiological leaks.

[0009] A solution to this problem has already been developed by the Applicant, and it is disclosed in document FR 3 114 907 Al. If this solution correctly meets the objective set of reducing the risks of radiological leaks, there remains, however, a need to optimize its design, in particular to facilitate the manufacture and installation of the radiological protection device.

[0010] STATEMENT OF THE INVENTION

[0011] To meet this need, the subject of the invention is a packaging for the transport and / or storage of radioactive materials, the packaging comprising a packaging body formed by a lateral body, a base and a removable cover, the base and the cover being spaced from each other along a longitudinal central axis of the packaging, and the body delimiting a cavity for housing the radioactive materials, the packaging comprising at least one radiological protection enclosure formed by enclosure wall elements, each radiological protection enclosure delimiting with its enclosure wall elements a single and unique space in which a radiological protection device is arranged.

[0012] According to the invention, the radiological protection device comprises a plurality of prefabricated radiological protection blocks following one another along a given direction of the packaging, so as to face each other in this same direction, within said same and unique space.

[0013] In addition, at least several of said plurality of blocks are each held on at least one of the enclosure wall elements by at least one holding member cooperating with this block and with said at least one of the associated enclosure wall elements.

[0014] Finally, said plurality of prefabricated blocks defines, within said same and unique space, several inter-block clearances in said given direction, each inter-block clearance being defined between two blocks arranged directly consecutively in this same direction. The invention advantageously makes it possible to simply limit or prohibit the spacing between the radiological protection blocks in the radiological protection enclosure, with the consequence of a significant reduction in the risk of radiological leaks between these prefabricated blocks.

[0015] The presence of inter-block clearances is not detrimental to the radiological protection function, since their possible accumulation remains limited, or even reduced to zero thanks to the holding devices of these blocks. On the contrary, inter-block clearances allow the thermal expansion of the prefabricated blocks, without risking too severely constraining the wall elements of the enclosure in which they are located.

[0016] Furthermore, for the realization of the invention, the shape of the prefabricated radiological protection blocks can advantageously remain simple, and therefore inexpensive. In addition, maintaining the blocks on the wall element(s) of the enclosure, via the holding members, constitutes an easy to implement, and inexpensive solution.

[0017] It is noted that another advantage of the proposed solution lies in obtaining an indexation of the prefabricated radiological protection blocks, in relation to the wall elements of the enclosure. This proves interesting, for example, when the blocks are made using different materials, and judiciously positioned in the enclosure to adapt locally to the observed radiation level.

[0018] Finally, another advantage of the invention is that it is possible to carry out a mechanical assembly of the elements from prefabricated components. Indeed, the prefabrication of the radiological protection blocks, in parallel with the manufacture of the other components of the packaging such as its cover, its side body, etc., makes it possible to reduce the manufacturing time of the packaging. In particular, it is neither necessary to provide a resin casting step, nor necessary to degas it.

[0019] The invention furthermore has at least one of the following optional features, taken alone or in combination.

[0020] According to a first preferred embodiment of the invention, the radiological protection enclosure is located at the level of the cover and it is formed by enclosure wall elements of the cover, said same and unique space extending over a given angular amplitude in a circumferential direction of the enclosure and of the packaging, first prefabricated radiological protection blocks succeeding one another along the circumferential direction so as to face each other in this same direction.

[0021] In addition, at least several of said first blocks are each held on at least one of two enclosure wall elements of the cover delimiting said same and unique space in a longitudinal direction of the enclosure and of the packaging, respectively in the two opposite directions of this direction, the holding being carried out by a first holding member housed in a first orifice of this first block, and also housed in a first orifice made on at least one of the two associated enclosure wall elements.

[0022] Preferably, each first block held by its first associated holding member is also held by a second holding member housed in a second orifice of this first block, and also housed in a second orifice made on at least one of the two associated enclosure wall elements, said second orifice in the first block being preferentially spaced radially from the first orifice in this first block.

[0023] Preferably, the first and / or second orifice in the first held block is oblong in shape, the length of which is oriented radially or substantially radially, and preferably only that of the two orifices which is radially furthest from the longitudinal central axis. This allows thermal expansion of the first blocks in the radial direction. This oblong shape could alternatively be adopted for both orifices, or even only for the one radially closest to the longitudinal central axis of the package. Similarly, when each first block has only the first orifice and not the second, the first may be oblong in shape extending in length in the radial or substantially radial direction.

[0024] When the previously mentioned orifices are not oblong in shape, they preferably adopt a circular shape.

[0025] Moreover, in this first preferred embodiment of the invention as well as in all the other embodiments, it is noted that each of the orifices is either blind or through. The holding members are preferably pins, rods, tie rods, bolts, rivets, or any other similar member. According to a possibility offered by this first embodiment, said same and single space also houses second prefabricated radiological protection blocks succeeding one another along the circumferential direction so as to face each other in this same direction, and at least several of said second blocks are each held on at least one of the two enclosure wall elements of the cover by said first holding member housed in a first orifice of this second block, and also housed in said first orifice made on at least one of the two associated enclosure wall elements.In addition, each first block covers, in the longitudinal direction, an inter-block clearance in said circumferential direction between two directly consecutive second blocks, and vice versa.

[0026] This configuration advantageously makes it possible to form two rows of blocks stacked in the longitudinal direction, to drastically limit leaks through the inter-block clearances. It is here preferentially provided to use the same first holding members to hold both the first and second prefabricated blocks, but separate holding members could be provided for the second blocks, without departing from the scope of the invention.

[0027] In this regard, it is indicated that as for the first maintained blocks, the second maintained blocks could be equipped with a second orifice. These first and second orifices of the second prefabricated blocks preferably have the same design as that of the first and second orifices of the first maintained blocks.

[0028] Moreover, it is noted that the first and second blocks preferably all have an identical design, the second blocks being arranged in said same and unique space in an inverted position relative to the position of the first blocks. This significantly reduces manufacturing costs, and greatly limits the risks of error in mounting the blocks in the radiological protection enclosure.

[0029] To do this, preferably, each first and second block has a radial fictitious median line, delimiting, on either side circumferentially of this fictitious line, two block portions including a holding portion comprising the first orifice, this first orifice being arranged along a radial fictitious median line of this holding portion. The same applies when a second orifice is also provided on the first and second blocks.

[0030] Preferably, said same and unique space extends over an angular amplitude of 360° in the circumferential direction. However, it could alternatively be several circumferentially segmented enclosures to reconstitute radiological protection over 360°, with in this case, each enclosure extending over an angular amplitude less than 360° and housing its own radiological protection device according to the principle of the invention.

[0031] In this first preferred embodiment of the invention, the first blocks thus form a crown using the blocks constituting angular sectors of this crown, spaced from each other at least for some of them, by circumferential inter-block clearances. The same applies to the second blocks, the latter being preferentially arranged in phase opposition with respect to the first blocks, so as to cover the circumferential inter-block clearances.

[0032] The following preferred embodiments apply to a radiological protection enclosure which is located around the cavity housing the radioactive materials.

[0033] According to a second preferred embodiment of the invention, the enclosure wall elements are arranged around the longitudinal central axis, said same and unique space extending over a given height in the longitudinal direction of the packaging, prefabricated radiological protection blocks succeeding one another along the longitudinal direction so as to face each other in this same direction.

[0034] In addition, at least several of said blocks are each held on at least one of two enclosure wall elements delimiting said same and unique space in a radial direction of the enclosure and of the packaging, respectively in the two opposite directions of this direction, the holding being carried out by a holding member housed in an orifice of the block, and also housed in an orifice made on at least one of the two associated enclosure wall elements.

[0035] Preferably, the two enclosure wall elements respectively form an inner shell and an outer shell centered on the longitudinal central axis. The inner shell could be placed around the packaging side body, or be formed by this same body.

[0036] Preferably, the blocks directly consecutive in the longitudinal direction partially overlap each other in the radial direction, so as to limit radiological leaks in this same radial direction. An alternative would be to provide two longitudinal rows of blocks radially overlapping each other, so as to obtain a principle identical or similar to that described for the first preferred embodiment, with said first and second blocks.

[0037] According to a third preferred embodiment of the invention, the radiological protection enclosure comprises two enclosure wall elements each taking the form of an annular structure and being stacked in the longitudinal direction, each annular structure centered on the longitudinal central axis comprising a radially external portion, and a radial portion extending radially from the radially external portion towards the longitudinal central axis and delimiting said same and unique space in the longitudinal direction, the annular structure delimiting an opening opposite the radial portion in the longitudinal direction, this opening being closed by the radial portion of the other annular structure which is stacked.

[0038] In addition, said same and unique space extends over a given angular amplitude along a circumferential direction of the enclosure and the packaging, first prefabricated radiological protection blocks succeeding one another along the circumferential direction so as to face each other in this same direction, and at least several of said first blocks are each held on at least one of the two enclosure wall elements in the form of an annular structure, the holding being achieved by a first holding member housed in an orifice of the first block, and also housed in a first orifice made on at least one of the two associated wall elements, preferably on the radial portion of at least one of them.

[0039] According to a possibility offered with this third preferred embodiment of the invention, said same and unique space also houses second prefabricated radiological protection blocks succeeding one another along the circumferential direction so as to face each other in this same direction. At least several of said second blocks are each held on at least one of the two enclosure wall elements in the form of an annular structure, by a second holding member housed in an orifice of this second block, and also housed in a second orifice made on at least one of the two associated wall elements, preferably on the radial portion of at least one of them. In addition, each first block covers, in the radial direction, an inter-block clearance in said circumferential direction between two directly consecutive second blocks, and vice versa.

[0040] If the first and / or second holding members implemented in this third embodiment can be of the type mentioned above, they preferably take the form of pins or through rods. In the latter case, each rod can pass through a block of each of several radiological protection enclosures which follow one another in the longitudinal direction of the packaging.

[0041] Other advantages and characteristics of the invention will appear in the detailed non-limiting description below.

[0042] BRIEF DESCRIPTION OF THE DRAWINGS

[0043] This description will be made with regard to the attached drawings, among which;

[0044] [Fig. 1] represents a schematic view in longitudinal axial section of a packaging for the transport and / or storage of radioactive materials, according to the invention;

[0045] [Fig. 2] represents a top view of the lid of the packaging shown in the preceding figure, and presented in the form of a first preferred embodiment of the invention;

[0046] [Fig. 3] represents a sectional view taken along line III-III of Figure 2;

[0047] [Fig. 4] represents a sectional view taken along line IV-IV of Figure 3;

[0048] [Fig. 5] represents a sectional view taken along line VV of Figure 4;

[0049] [Fig. 6] is a top view of one of the first prefabricated radiological protection blocks implemented in the first preferred embodiment of the invention;

[0050] [Fig. 7] is a top view of one of the second prefabricated radiological protection blocks implemented in the first preferred embodiment of the invention; [Fig. 8] is a partial longitudinal sectional view of a package according to a second preferred embodiment of the invention;

[0051] [Fig. 9] represents a cross-sectional view of the packaging, which is presented according to an alternative to the second embodiment of Fig. 8;

[0052] [Fig. 10] represents a partial view in longitudinal half-section of a package according to a third preferred embodiment of the invention, this figure 10 corresponding to the section taken along line XX of figure 11;

[0053] [Fig. 11] represents a partial cross-sectional view taken along line XI-XI of Fig. 10;

[0054] [Fig. 12] is a partial perspective view of one of the annular structures forming one of the radiological protection enclosures on the package shown in Figures 10 and 11; and

[0055] [Fig. 13] shows a cross-sectional view of the packaging, which is presented according to an alternative to the third embodiment of Figures 10 to 12.

[0056] DETAILED DISCLOSURE OF PREFERRED EMBODIMENTS

[0057] Referring firstly to Figure 1, there is shown a packaging 1 for the transport and / or storage of radioactive materials, such as nuclear fuel assemblies 3 or radioactive waste (shown only partially and schematically in Figure 1).

[0058] This package 1 is shown in a vertical storage / warehousing position, in which its longitudinal central axis 2 is oriented vertically. It rests on a packaging base 4, opposite a removable cover 6 in the direction of the height 8, parallel to the longitudinal axis 2. The direction of the height 8, shown diagrammatically in FIG. 1, thus corresponds to the longitudinal direction of the package, while its radial direction is represented by the arrow 11, and its circumferential / tangential direction by the arrow 13. These directions 8, 11, 13 are associated with the package 1 as a whole, but also with each of its components, in particular with the radiological protection enclosures which will be described later. Between the base 4 and the cover 6, the package 1 comprises a lateral body 10 extending around the axis 2, and internally delimiting a cavity 12 for housing the radioactive materials 3.This cavity 12 may constitute a containment enclosure intended to receive the radioactive materials, for example arranged in a storage basket also located in the containment enclosure. Alternatively, the containment enclosure is defined entirely by a case, also called a "canister", placed in the aforementioned cavity 12. This is closed axially upwards by the cover 6, and downwards by the bottom 4, which may be made in one piece with the lateral body 10 of the packaging. These elements 4, 6 and 10 in fact form the body of the packaging, dedicated in particular to ensuring the mechanical strength of the packaging in the event of a fall, so as to maintain the tightness of the containment enclosure.

[0059] At its periphery and around the axis 2, the packaging 1 is also equipped with a radiological protection enclosure 14 delimiting an annular space in which a neutron protection device 16 is arranged. This device 16 may be conventional, or else respond to the principle of the invention, as will be explained in detail later, in a second preferred embodiment of the invention. It is noted that the enclosure 14 is formed using several enclosure wall elements delimiting the annular space 15, in particular an inner shell 20 and an outer casing 22, both centered on the axis 2. Here, the inner shell 20 is a part added around the lateral body 10 of the packaging, but alternatively, the internal delimitation of the annular space 15 could be directly produced by the external surface of the lateral body 10. The outer casing 22 forms the lateral periphery of the packaging 1.

[0060] The radiological protection device 16 is here a neutron protection device, produced for example using prefabricated blocks stacked in the direction 8 in the annular space 15. Each prefabricated radiological protection block is preferably made of cast resin. This resin may comprise boron or any other neutron-absorbing element, i.e. neutron-absorbing elements. By "neutron-absorbing elements" is meant elements which have an effective cross-section greater than 100 barns for thermal neutrons. The elements 10, 20, 22 of the packaging may be metallic, for example made of steel or cast iron. In the annular space 15, also called the inter-shell space, no thermal conductors are preferably provided in addition to the protection blocks. This particular case corresponds to packaging intended for the transport of radioactive materials releasing only a low thermal power, or even none at all.By "thermal conductors" is meant conductors conventionally implemented in packaging, generally arranged alternately with the neutron protection blocks and connecting the inner shell 20 to the outer casing 22. Nevertheless, thermal conductors in the form of annular discs could be envisaged. The blocks then alternate with the thermal conduction discs in direction 8.

[0061] At the level of the cover 6, another radiological protection enclosure 24 is provided, which is here unique within the cover, and which delimits a single annular space 26 centered on the axis 2. In this space 26, in the form of a crown, a neutron protection device 28 is arranged, specific to the present invention and which is the subject of a first preferred embodiment thereof.

[0062] With reference jointly to Figures 1 to 7, the enclosure 24 of the first embodiment is formed using several wall elements of the cover, in particular an inner cowling 30 and an outer cowling 32 spaced apart from each other in the direction 8, and each orthogonal to this same direction. These cowlings 30, 32 could respectively form the axially inner and outer walls of the cover, or else be housed inside it. Other enclosure wall elements are provided to radially close the single annular space 26, thus extending uninterruptedly over 360° around the axis 2, on which the cover 6 is also centered. Alternatively, several radiological protection enclosures in the form of distinct angular sectors could be arranged adjacent in the circumferential direction 13, without departing from the scope of the invention.In such a case, each unique space 26, associated with a given enclosure 24, then extends along an angular amplitude of less than 360° along the circumferential direction 13.

[0063] The radiological protection device 28 is here a neutron protection device, produced using prefabricated radiological protection blocks 30a, 30b. Each prefabricated block 30a, 30b is preferably made of cast resin. Then, to size them, a final cut is made on the cast resin, for example with a water jet. This resin may include boron or any other neutron-absorbing element, in the sense mentioned above.

[0064] The enclosure wall elements 30, 32 of the packaging cover may be metallic, for example steel or cast iron. In the single annular space 26, in the form of a crown centered on the axis 2, no thermal conductors are preferably provided in addition to the protection blocks. This space 26 is in fact preferably only occupied by the blocks 30a, 30b, and by their holding members which will be described later.

[0065] In this first preferred embodiment of the invention, the blocks are divided into first blocks 30a forming a first annular row of blocks centered on the axis 2, and into second blocks 30b forming a second annular row of blocks centered on the axis 2. The two rows, each comparable to a crown formed by blocks each constituting an angular sector of this same crown, are thus stacked one on top of the other within the space 26, in the direction 8. In the figures, the row of first blocks 30a corresponds to that which is located furthest from the cavity 12 housing the radioactive materials.

[0066] Concerning this annular row of first blocks 30a, these therefore follow one another in the circumferential direction 13, so as to face each other in this same direction, within the same and unique space 26. At least several of these first blocks 30a define between them circumferential inter-block clearances 34, each corresponding to a space left empty between two directly consecutive blocks 30a in the direction 13. Preferably, such a clearance 34 is provided on either side of each block 30a of the device 28, even if certain blocks could be in contact with each other in the direction 13, without departing from the scope of the invention.

[0067] All the first blocks 30a are preferably identical or substantially identical. Overall, each block 30a is made from a single piece in the shape of an angular sector, extending over an amplitude for example of the order of 15 to 45°, being flattened in the direction 8. One of the particularities of the invention lies in the implementation of means for limiting / prohibiting the circumferential spacing between the first adjacent blocks 30a, and thus preventing the accumulation of such spacings from leading to neutron leaks of an unacceptable level between two directly consecutive blocks 30a. In other words, the invention provides a judicious solution making it possible to retain all or part of the inter-block clearances 34, and to ensure that in the event of a possible accumulation between the latter, the extent of the accumulation remains controlled and acceptable.

[0068] To do this, it is provided that several first blocks 30a, and preferably all or almost all of them, are each held on at least one of the two cowlings 30, 32 delimiting the space 26 in the direction 8, respectively in the two opposite directions of this direction, namely upwards and downwards. Thanks to this embodiment, in addition to limiting the risks of accumulation of the circumferential inter-block clearances 34, the connection of these blocks 30a to one or both cowlings 30, 32 of the cover makes it possible to obtain and maintain an indexing of these blocks relative to the other elements 30, 32 of the cover.

[0069] For each of the first blocks 30a concerned, their maintenance is achieved by a first maintenance member 36a housed in a first orifice 38a of this first block, and also housed in a first orifice 40a made on at least one of the two cowlings 30, 32. Preferably, the maintenance member 36a is a pin of circular section oriented in the direction 8. It is fixed at its two opposite ends on the two cowlings 30, 32, in the orifices 40a of the latter, and it passes through the first orifice 38a of the block 30a with or without play.

[0070] This first holding member 36a is preferably located near an inner radial end of the block 30a. It makes it possible to limit / prevent its circumferential movement, respectively relative to each of the two first blocks 30a located on either side of the latter in the circumferential direction 13.

[0071] To reinforce the holding and indexing of each of these first blocks 30a held by the first member 36a, each block is also held by a second holding member 36b housed in a second orifice 38b of this first block, and also housed in a second orifice 40b made on each of the two cowlings 30, 32. The second orifice 38b through the block 30a is radially spaced from the first orifice 38a, being located close to an outer radial end of this block. It is therefore entirely crossed by the second holding member 36b, also preferably in the form of a pin of circular section oriented in the direction 8. This second member 36b is fixed at its two opposite ends on the two cowlings 30, 32, in the orifices 40b of the latter, and it passes with play through the second orifice 38b of the block 30a, the shape of which is oblong with a length oriented radially or substantially radially.This configuration allows thermal expansion of the block 30a, in the radial direction 11.

[0072] As indicated previously, the first blocks 30a all have an identical or substantially identical design, to facilitate their manufacture. As can be seen in FIG. 6, the first block 30a has a radial imaginary center line 42, delimiting, on either side of it in the direction 13, a solid portion 44 and a holding portion 46 comprising the two orifices 38a, 38b. These two portions 44, 46 form two half-block sectors, of the same angular amplitude. The two through orifices 38a, 38b, with axes orthogonal to the plane in which this crown sector 30a is inscribed, are arranged along a radial imaginary center line 48 of the holding portion 46.

[0073] This specific design makes it possible, when the block 30a is turned over on itself, to form a second block 30b for producing the second annular row, in which the position of the holding orifices within the second blocks 30b is reversed with respect to that within the first blocks 30a. Indeed, as can be seen in FIG. 7 showing a second block 30b also in top view, the position of the solid 44 and holding 46 portions is reversed along the direction 13.

[0074] Thus, all the blocks 30a, 30b of the radiological protection device 28 are of identical or substantially identical design, only their positioning differing depending on whether the block belongs to the first or second annular row of radiological protection.

[0075] Concerning the annular row of second blocks 30b, the latter also follow one another in the circumferential direction 13, so as to face each other in this same direction, always in the same and unique space 26. At least several of these second blocks 30b define circumferential inter-block clearances 50, each corresponding to a space left empty between two directly consecutive blocks 30b in the direction 13. Preferably, such a clearance 50 is provided on either side of each block 30b of the device 28, even if certain blocks 30b could be in contact with each other in the direction 13, without departing from the scope of the invention.

[0076] To limit / prohibit the circumferential spacing between the adjacent second blocks 30b, and thus prevent the accumulation of such spacings from leading to neutron leaks of an unacceptable level between two directly consecutive blocks 30b, it is provided that several first blocks 30b, and preferably all or almost all of them, are each held on at least one of the two cowlings 30, 32. For each of the second blocks 30b concerned, their holding is here achieved by the first holding member 36a housed in a first orifice 58a of this second block, passing through and aligned with a first orifice 38a of one of the first blocks 30a adjacent in the direction 8.

[0077] Furthermore, the second block 30b is also held by the second holding member 36b, which passes through a second orifice 58b of this second block, aligned with the second orifice 38b of one of the first blocks 30a adjacent in the direction 8. Here also, the crossing takes place with play in the radial direction 11, since the second orifice 58b of the block 30b has the same oblong shape of length oriented radially or substantially radially.

[0078] The first blocks 30a of the first annular row are thus circumferentially offset from the second blocks 30b of the second annular row axially covered by the first. This offset corresponds to half the angular amplitude of each of these blocks 30a, 30b, generating an arrangement of the two rows called "in phase opposition". Thanks to this arrangement, each first block 30a thus covers, in the direction 8, one of the inter-block clearances 50 between two directly consecutive second blocks 30b of the second row, in the same way that each second block 30b covers, still in the direction 8, one of the inter-block clearances 34 between two directly consecutive first blocks 30a of the first row.

[0079] According to a second preferred embodiment of the invention shown in Figure 8, the principle of the invention is implemented around the cavity 12 for housing the radioactive materials, at the level of the aforementioned enclosure 14. Here, the enclosure 14 is formed using several enclosure wall elements delimiting the annular space 15, and being arranged around the axis 2. This is in particular the external casing 22 and the lateral body 10 each in the form of a ferrule, and delimiting the same and single annular space 15 in a radial direction 11, respectively in the two opposite directions of this direction. Alternatively, as described with reference to Figure 1, an inner ferrule could be arranged around the lateral body 10 to delimit the space 15 radially inwards. This same and unique annular space 15 preferably extends over the entire height of the cavity 12, in the direction 8.Nevertheless, while retaining the principle of the second preferred embodiment which will be described below, the enclosure 15 could be segmented along the direction 8, and / or along the direction 13, so as to form several adjacent enclosures along one and / or the other of these two directions.

[0080] Prefabricated radiological protection blocks 60 follow one another along the direction 8, so as to face each other in this same direction. Each of them here takes the form of a thin crown, the crowns then following one another in the direction 8, while leaving longitudinal inter-block clearances 62 between them. Each inter-block clearance 62 corresponds to a space left empty between two directly consecutive blocks 60 in the direction 8. Preferably, such a clearance 62 is provided on either side of each block 60 of the device 16, even if certain blocks could be in contact with each other in the direction 8, without departing from the scope of the invention.

[0081] Here too, all the first blocks 60 are preferably identical or substantially identical. Overall, each block 60 is made from a single piece whose half-section is generally Z-shaped, with the central branch, oriented in the direction 11, which is orthogonal to the other two branches, oriented in the direction 8. This particular shape allows the directly consecutive blocks 60 to partially overlap each other, in the radial direction 11, in order to limit radiological leaks.

[0082] At least several of the blocks 60, namely for example all of them or most of them, or for example one block out of two, are each held on the external casing 22 by a holding member 36 in the form of a pin housed in an orifice 38 of the block 60, and also housed in an orifice 40 made on the external casing 22. The pin 36 can be fixed in the orifice 40, preferably through the casing 22, and its other end is housed fixed or simply fitted in the orifice 38, preferably blind, of the block 60. The pin 36 and its associated orifices 38, 40 are preferably oriented in the radial direction 11, or substantially in this direction.

[0083] According to an alternative to the second preferred embodiment, visible in Figure 9, the single annular space 15 is filled with blocks 60 each extending over the entire height of this space, forming a simple angular sector. The blocks 60 thus reconstitute a crown around the axis 2, following one another in the direction 13 and forming circumferential inter-block clearances 62 between them. The blocks 60 are here also all preferably identical or substantially identical. Overall, each block 60 is made from a single piece whose cross-section is generally Z-shaped, with the central branch, oriented in the direction 11, which is orthogonal to the other two branches, oriented in the direction 13. This particular shape allows the directly consecutive blocks 60 to partially overlap each other, in the radial direction 11, in order to limit radiological leaks.

[0084] At least several of the blocks 60 are held in a manner identical or analogous to that set out above, with the pins 36 radially passing through the orifices 38, 40 provided respectively on the blocks 60 and on the external casing 22.

[0085] According to a third preferred embodiment of the invention shown in Figures 10 to 12, the principle of the invention is still implemented around the cavity 12 for housing the radioactive materials, but with a radiological protection enclosure 14a in the form of a crown around the cavity 12, over a reduced height.

[0086] Indeed, there are several distinct annular enclosures 14a which follow one another in the direction 8 along the cavity 12, each of them being essentially formed using two enclosure wall elements 64 each taking the form of an annular structure, and being stacked on top of each other in the direction 8. These cumulative enclosures 14a extend over the entire height of the cavity 12, or substantially over this entire height.

[0087] Each annular structure 64 is centered on the axis 2, and it comprises a radially external portion 66, a radially internal portion 68, and a radial portion 70 extending radially from the radially external portion to the radially internal portion 68. The generally U-shaped half-section of the annular structure 64 delimits, opposite the radial portion 70 in the direction 8, an opening 71 which is closed by the radial portion 70 of the annular structure 64 directly consecutive to it. The annular space 15a is thus delimited radially in both directions respectively by the two walls 66, 68 of one of the annular structures 64, and delimited axially in both directions respectively by the radial portion 70 of this same structure 64, as well as by the radial wall 70 of the structure 64 directly consecutive to it in the stack in the direction 8.

[0088] Alternatively, each annular structure 64 may not include the radially internal portion 68, and therefore have a generally L-shaped half-section. The radial delimitation towards the inside of each annular cavity 15a is then produced with the radially external surface of the lateral packaging body 10. Similarly, it is indicated that if the radial portion 70 is shown flat, it could however include a step in the direction 8.

[0089] Any two annular structures 64 which are directly consecutive in the direction 8 form a single space 15a of equally annular geometry, even if segmentation along the circumferential direction 13 remains possible, without departing from the scope of the invention.

[0090] The radiological protection device 16a housed in the space 15a of each enclosure 14a is also made up of blocks, here first blocks 72a and second blocks 72b, respectively intended to form two concentric annular rows, centered on the axis 2. The first and second blocks 72a, 72b are preferably all of identical or substantially identical shape, for example generally parallelepipedal, or having a slight curvature in the circumferential direction in order to adapt to the curvature of the same and unique space 15a in this same direction.

[0091] More precisely, the first prefabricated radiological protection blocks 72a form the inner row, and they follow one another along the direction 13 so as to face each other in this same direction, and leaving several circumferential inter-block clearances 74 visible, in the same sense as that described previously. Similarly, the second prefabricated radiological protection blocks 72b form the outer row, and they also follow one another along the direction 13 so as to face each other in this same direction, and leaving several circumferential inter-block clearances 76 visible in FIG. 11.

[0092] To ensure the maintenance of each of several of the first blocks 72a, or even all of them, each of them is maintained relative to the radial portion 70 of the annular structure 64 in which it rests, by a first maintenance pin 78a housed in an orifice 80 of the block 72a, and also housed in a first orifice 82a made on said radial portion 70 and opening into the single annular space 15a. The first pin 78a can be fixed or simply fitted into each of these two orifices 80, 82a, preferably blind.

[0093] The pin 78a in the bottom of the space 15a, as well as its associated orifices 80, 82a, are preferably oriented in the longitudinal direction 8, or substantially in this direction.

[0094] Similarly, to ensure the maintenance of each of several of the second blocks 72b, or even all of them, each of them is maintained relative to the radial portion 70 of the annular structure 64 in which it rests, by a second maintenance pin 78b housed in an orifice 80 of the block 72b, and also housed in a second orifice 82b made on the radial portion 70. Here too, the second pin 78b can be fixed or simply fitted into each of these two associated orifices 80, 82b, preferably blind. The second pin 78b in the bottom of the space 15a, as well as its two associated orifices 80, 82b, are preferably also oriented in the longitudinal direction 8, or substantially in this direction.

[0095] The first blocks 72a of the first annular row are circumferentially offset from the second blocks 72b of the second annular row. This offset corresponds to half the angular amplitude of each of these blocks 72a, 72b, generating an arrangement of the two rows called "in phase opposition". Thanks to this arrangement, each first block 72a thus covers, in the direction 11, one of the inter-block clearances 76 between two directly consecutive second blocks 72b of the second row, in the same way that each second block 72b covers, still in the direction 11, one of the inter-block clearances 74 between two directly consecutive first blocks 72a of the first row. According to an alternative shown in FIG. 13, it is the same first through rod 84a, oriented in the direction 8, which serves to hold a first block 72a of several stacked enclosures 14a.Indeed, this rod 84a passes through several first blocks 72a aligned along the direction 8 and belonging to separate enclosures 14a. It may be a first block of all the annular enclosures 14a equipping the packaging 1. In such a case, at least some of the orifices 80, 82a are through-holes to allow the rod 84a to pass. Several first rods 84a of this type can thus cooperate with the blocks 72a of the first row.

[0096] One or more second through rods (not shown) of the same type may be used to hold second blocks 72b of the second annular row.

[0097] Of course, various modifications may be made by those skilled in the art to the invention which has just been described, solely by way of non-limiting examples and within the scope defined by the appended claims. In particular, the various preferred embodiments described above may be combined, and their characteristics remain interchangeable. For example, solutions involving blocks partially overlapping each other, within the same row, may be replaced by solutions with two distinct rows of blocks overlapping each other, and vice versa.

Claims

CLAIMS 1. Packaging (1) for the transport and / or storage of radioactive materials, the packaging comprising a packaging body formed by a lateral body (10), a bottom (4) and a removable cover (6), the bottom and the cover being spaced from each other along a longitudinal central axis (2) of the packaging, and the body delimiting a cavity (12) for housing the radioactive materials (3), the packaging comprising at least one radiological protection enclosure (14, 14a, 24) formed by enclosure wall elements (20, 22, 30, 32, 64), each radiological protection enclosure delimiting with its enclosure wall elements a single and same space (15, 15a, 26) in which a radiological protection device (16, 16a, 28) is arranged, characterized in that the radiological protection device comprises a plurality of prefabricated radiological protection blocks (30a, 30b, 60, 72a, 72b) following one another along a given direction (8, 13) of the packaging,so as to face each other in this same direction, within said same and single space (15, 15a, 26), at least several of said plurality of blocks (30a, 30b, 60, 72a, 72b) being each held on at least one of the enclosure wall elements (20, 22, 30, 32, 64) by at least one holding member (36, 36a, 36b, 78a, 78b, 84a) cooperating with this block and with said at least one of the associated enclosure wall elements, said plurality of prefabricated blocks defining, within said same and single space, several inter-block clearances (34, 50, 62, 74, 76) along said given direction (8, 13), each inter-block clearance being defined between two blocks arranged directly consecutively along this same direction., 2. Packaging according to claim 1, characterized in that the radiological protection enclosure (24) is located at the level of the cover (6) and it is formed by enclosure wall elements (30, 32) of the cover, said same and single space (26) extending over a given angular amplitude in a circumferential direction (13) of the packaging, first prefabricated radiological protection blocks (30a) succeeding one another along the circumferential direction (13) so as to face each other in this same direction, and in that at least several of said first blocks (30a) are each held on at least one of two enclosure wall elements (30, 32) of the cover delimiting said same and single space (26) in a longitudinal direction (8) of the enclosure and of the packaging, respectively in the two opposite directions of this direction, the holding being carried out by a first holding member (36a) housed in a first orifice (38a) of this first block, and also housed in a first orifice (40a) made on at least one of the two associated enclosure wall elements (30, 32).

3. Packaging according to claim 2, characterized in that each first block (30a) held by its first associated holding member (36a) is also held by a second holding member (36b) housed in a second orifice (38b) of this first block, and also housed in a second orifice (40b) made on at least one of the two associated enclosure wall elements (30, 32), said second orifice (38b) in the first block being preferentially spaced radially from the first orifice (38a) in this first block.

4. Packaging according to claim 2 or claim 3, characterized in that the first and / or second orifice (38b) in the first held block (30a) is oblong in shape, the length of which is oriented radially or substantially radially, and preferably only that of the two orifices which is radially furthest from the longitudinal central axis (2).

5. Packaging according to any one of claims 2 to 4, characterized in that said same and single space (26) also houses second prefabricated radiological protection blocks (30b) succeeding one another along the circumferential direction (13) so as to face each other in this same direction, in that at least several of said second blocks (30b) are each held on at least one of the two enclosure wall elements (30, 32) of the cover by said first holding member (36a) housed in a first orifice (58a) of this second block, and also housed in said first orifice (40a) made on at least one of the two associated enclosure wall elements (30, 32), and in that each first block (30a) covers, in the longitudinal direction (8), an inter-block clearance (50) in said circumferential direction (13) between two directly consecutive second blocks (30b), and vice versa.

6. Packaging according to claim 5, characterized in that the first and second blocks (30a, 30b) all have an identical design, the second blocks (30b) being arranged in said same and unique space (26) in an inverted position relative to the position of the first blocks (30a).

7. Packaging according to claim 6, characterized in that each first and second block (30a, 30b) has a radial fictitious median line (42), delimiting, on either side circumferentially of this fictitious line, two block portions including a holding portion (46) comprising the first orifice (38a, 58a), this first orifice being arranged along a radial fictitious median line (48) of this holding portion (46).

8. Packaging according to any one of claims 2 to 7, characterized in that said same and single space (26) extends over an angular amplitude of 360° in the circumferential direction (13).

9. Packaging according to claim 1, characterized in that the radiological protection enclosure (14, 14a) is located around the cavity housing the radioactive materials.

10. Packaging according to claim 9, characterized in that the enclosure wall elements (10, 22) are arranged around the longitudinal central axis (2), said same and single space (15) extending over a given height in the longitudinal direction (8) of the packaging, prefabricated radiological protection blocks (60) succeeding one another along the longitudinal direction (8) so as to face each other in this same direction, and in that at least several of said blocks (60) are each held on at least one of two enclosure wall elements (20, 22) delimiting said same and single space (15) in a radial direction (11) of the enclosure and of the packaging, respectively in the two opposite directions of this direction, the holding being carried out by a holding member (36) housed in an orifice of the block (38), and also housed in an orifice (40) made on at least one of the two associated enclosure wall elements (20, 22).

11. Packaging according to claim 10, characterized in that the two enclosure wall elements (20, 22) respectively form an inner shell and an outer shell centered on the longitudinal central axis (2).

12. Packaging according to claim 10 or claim 11, characterized in that the blocks (60) directly consecutive in the longitudinal direction (8) partially overlap each other in the radial direction.

13. Packaging according to claim 9, characterized in that the radiological protection enclosure (14a) comprises two enclosure wall elements (64) each taking the form of an annular structure and being stacked in the longitudinal direction (8), each annular structure (64) centered on the longitudinal central axis comprising a radially external portion (66), and a radial portion (70) extending radially from the radially external portion towards the longitudinal central axis (2) and delimiting said same and only space (15a) in the longitudinal direction (8), the annular structure (64) delimiting an opening (71) opposite the radial portion (70) in the longitudinal direction, this opening (71) being closed by the radial portion (71) of the other annular structure (64), said same and only space (15a) extending over a given angular amplitude in a circumferential direction (13) of the enclosure and the packaging,first prefabricated radiological protection blocks (72a) succeeding one another along the circumferential direction so as to face each other in this same direction, and in that at least several of said first blocks (72a) are each held on at least one of the two enclosure wall elements (64) in the form of an annular structure, the holding being achieved by a first holding member (78a, 84a) housed in an orifice (80) of the first block, and also housed in a first orifice (82a) made, on at least one of the two associated wall elements (64), preferably on the radial portion (70) of at least one of them.

14. Packaging according to claim 13, characterized in that said same and single space (15a) also houses second prefabricated radiological protection blocks (72b) succeeding one another along the circumferential direction (13) so as to face each other in this same direction, in that at least several of said second blocks (72b) are each held on at least one of the two enclosure wall elements (64) in the form of an annular structure, by a second holding member (78b) housed in an orifice (80) of this second block, and also housed in a second orifice (82b) made on at least one of the two associated wall elements (64), preferably on the radial portion (70) of at least one of them, and in that each first block (72a) covers, in the radial direction (11), an inter-block clearance (76) in said direction circumferential (13) between two second blocks (72b) directly consecutive, and vice versa. 15.Packaging according to claim 13 or claim 14, characterized in that the first and / or second holding member (78a, 78b, 84a) has the shape of a pin or a through rod.

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