Classifications

• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
  • G21F5/00—Transportable or portable shielded containers
  • G21F5/005—Containers for solid radioactive wastes, e.g. for ultimate disposal
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
  • G21F5/00—Transportable or portable shielded containers
  • G21F5/005—Containers for solid radioactive wastes, e.g. for ultimate disposal
  • G21F5/008—Containers for fuel elements
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
  • G21F5/00—Transportable or portable shielded containers
  • G21F5/06—Details of, or accessories to, the containers
  • G21F5/10—Heat-removal systems, e.g. using circulating fluid or cooling fins

Definitions

• the invention relates to the field of packaging for the transport and / or storage of radioactive materials, preferably of the type of irradiated nuclear fuel assemblies.
• storage devices also called “baskets” or “racks” storage. These storage devices, usually of cylindrical shape and of substantially circular or polygonal section, are able to receive the radioactive materials.
• the storage device is intended to be housed in the cavity of a package to form together with it a container for the transport and / or storage of radioactive materials, in which they are perfectly confined.
• the aforesaid cavity is generally defined by a lateral body extending along a longitudinal axis of the package, as well as a bottom and a package cover arranged at opposite ends of the body, in the direction of the longitudinal axis.
• the lateral body comprises an inner wall and an outer wall, generally taking the form of two concentric metallic shells together forming an inter-wall annular space inside which thermal conductors are housed, as well as radiological protection means, in particular to form a barrier against neutrons emitted by the radioactive material housed in the cavity.
• This neutron shielding is conventionally carried out using a material called "resin concrete".
• the thermal conductors make it possible to conduct the heat released by the radioactive materials towards the outside of the container, in order to avoid any risk of overheating which may cause degradation of these materials, an alteration of the mechanical properties of the materials constituting the packaging, or an abnormal pressure rise in the cavity.
• Thermal conductors have been the subject of many developments, which have led to various achievements.
• One of the most commonly used resides in the placement of fins in the inter-wall space, so that their opposite ends are respectively in contact with the two rings in order to create thermal bridges.
• These fins which extend in length in the direction of the longitudinal axis of the package, and allow to conduct the heat of the inner shell to the outer shell.
• radiological protection blocks between the fins in the inter-wall space of the lateral body.
• each thermal conductor comprises at least one member for traversing the inter-wall space, and at one end of this passage member, a first support member and fitting on one of the walls. inner and outer side packing body. Generally, at the other end of the conductor, there is provided a second support member and connector on the other of the two walls.
• Each support and coupling member also has a plurality of attachment points on its associated wall of the lateral packaging body, these attachment points usually taking the form of through holes for fixing screws on the walls of the body. lateral.
• the thermal conductors and the walls of the lateral body are generally made of materials having different coefficients of thermal expansion.
• the conductors are generally made of copper, aluminum or their alloys, and the inner and outer walls of steel. Consequently, the mounting made at the fixing points must be able to take into account the phenomena of differential thermal expansion between these elements, without generate mechanical stresses likely to alter their mechanical connection.
• the assembly must avoid any deformation of the support member which could affect the good contact of this body with the wall on which it is attached, and thus compromise the heat transfer between the wall and the conductor.
• the object of the invention is therefore to remedy at least partially the disadvantages mentioned above, relating to the embodiments of the prior art.
• the subject of the invention is a packaging for transporting and / or storing radioactive materials, comprising a lateral body equipped with an inner wall and an outer wall defining between them an inter-wall space in which is arranged at least one thermal conductor, the inner wall defining a housing cavity for the radioactive materials, said thermal conductor comprising at least one member for traversing the inter-wall space, and, at one end of this passage member a first support and coupling member on one of said inner and outer walls of the lateral packaging body, said first wall, said first support and coupling member having a plurality of first fixing points on the first wall of the lateral packaging body, said first fixing points being spaced from each other in a longitudinal direction of the thermal conductor.
• said first support member and coupling member is segmented in said longitudinal direction, so as to define first segments spaced apart from each other by first slots arranged between said first attachment points, each first slot extending through said through member defining a closed end of said first slot.
• the first segments can expand without constraint on either side of their attachment points, towards their ends, by consuming the width of the slots forming gaps between the segments.
• the proposed solution no longer requires the presence of oblong holes as in the prior art, and above all allows a firm attachment of the attachment points on their respective walls, for obtaining a better heat transfer.
• the invention is therefore no longer subject to the antagonistic effects resulting from the tightening of the screws at the attachment points, as was the case previously.
• the ratio between the width of each first slot and the length, in the longitudinal direction, of any one of the first two segments arranged on either side of this slot is between 0.005 and 0.1.
• each first slot extends through the passage member at a distance which represents 40 to 90% of the total width of the passage member in the direction of the slot.
• each first slot extends substantially orthogonal to the longitudinal direction of the thermal conductor. These slots could nevertheless be inclined differently, without departing from the scope of the present invention.
• said first support member and coupling member and said traversing member are each of substantially flat shape, parallel to the longitudinal direction. These two elements are preferably intersecting, for example forming a V with an internal angle of between 90 and 150 °.
• a second support member Preferably, at the other end of said bushing member, there is provided a second support member, and possibly a coupling, on said other of said inner and outer walls of the lateral packaging body, said second wall.
• the second support member is in the continuity of said traversing member, sandwiched between two sectors of the second wall, here in general the outer wall of the main body.
• said second support member is segmented in said longitudinal direction, so as to define second segments spaced apart from each other by second slots each extending through said passage member defining a closed end of said second slot.
• these second slots provide more flexibility to the support member clamped between the sectors of the second wall, and thus improve the overall flexibility of the thermal conductor.
• the second support member is supported on a surface of said second wall defining the inter-wall space, and possibly connected thereto.
• the conductor then preferably has a section in the overall shape of S or Z, with projecting angles between the traversing member and each of the two support members preferably between 90 and 150 °.
• the second support member is preferably segmented in said longitudinal direction, so as to define second segments spaced apart from each other by second slots each extending through said passage member defining a closed end of said second slot.
• the second support member could be continuous, that is to say without slot, without departing from the scope of the invention.
• the second slot solution is in particular retained when the second support member has a plurality of second attachment points on the second wall of the packaging side body, said second attachment points being arranged between the second slots separating the second segments. .
• the benefit of these second slots is then comparable to that of the first slots, as described above.
• this also makes it possible to improve the behavior of the thermal conductor with regard to the mechanical stresses generated during thermal expansion. , especially in the case where the first slots would have only a short length on the traversing member.
• these second slots confer increased overall flexibility to the thermal conductor.
• the driver may comprise the following elements:
• first or second support member secured to said other through member, so that said elements together define a general form of ⁇ (uppercase omega), said other first or second support member being segmented according to said longitudinal direction, so as to define first or second segments spaced apart from each other, each first or second slot extending each through said other bushing member defining a closed end of said first or second slot.
• This embodiment can therefore comprise either two first support members and a second support member, or two second support members and a first support member, these support members being in both cases connected by the two crossing bodies.
• the second support members may or may not have second attachment points, depending on the desired needs.
• ⁇ uppercase omega
• the shape of ⁇ is crossed by slots each running through a part of each of the two crossing members, through the support member which connects them. These slots thus take a general shape of U contributing to obtaining a great flexibility of the thermal conductor.
• the conductor has a generally undulating shape, with radially external peaks and alternately alternating radially internal peaks, the generally wavy shape defining:
• each external pattern being made from a first or a second support member and with the aid of two traversing members; extending on either side of this support organ;
• each slot passing through the support member and a portion of each of the two members passing through its associated pattern.
• This configuration is similar to the realization, in one piece, of several adjacent thermal conductors in the form of ⁇ such as that described above.
• Each conductor can thus extend in one piece over a large angular sector of the inter-wall annular space, for example over 45 ° to 180 °.
• said first slots and said second slots alternate preferably alternately in said longitudinal direction. Nevertheless, other configurations can be envisaged in the distribution of the first and second slots, without departing from the scope of the invention.
• said first support and coupling member is mounted on the first wall, at said first attachment points, by screwed elements. or by welding. It is the same for the second attachment points when they are provided on the second support member and coupling.
• said first wall of the lateral packaging body is preferably the inner wall, but could alternatively be the outer wall.
• FIG. 1 shows a cross-sectional view of a container comprising a transport packaging and / or storage of radioactive material according to the invention
• FIGS. 2 to 9 show various preferred embodiments for the thermal conductors fitted to the inter-wall space of the lateral body of the package shown in FIG. 1.
• the container 1 generally comprises a packaging 2 object of the present invention, inside which there is a storage device 4, also called storage basket.
• the device 4 is intended to be placed in a housing cavity 6 of the package 2, as shown schematically in FIG. 1, in which it is also possible to see the longitudinal axis 8 of this package, coinciding with the longitudinal axes. storage device and the housing cavity.
• the term "longitudinal” should be understood as parallel to the longitudinal axis 8 and the longitudinal direction of the package.
• the container 1 and its device 4 forming receptive housing assemblies of nuclear fuel are here shown in a horizontal position / lying usually adopted during the transportation of the assemblies, different from the vertical position of loading / unloading fuel assemblies.
• the package 2 essentially has a bottom (not shown) on which the device 4 is intended to rest in a vertical position, a lid (not shown) arranged at the other longitudinal end of the package , and a lateral body 10 extending around and along the longitudinal axis 8, that is to say in the longitudinal direction of the container 1.
• this lateral body 10 which defines the housing cavity 6, and more particularly an internal wall 20 by means of a lateral internal surface 12 of substantially cylindrical shape and of circular section, and of axis coinciding with the axis 8.
• the design of the lateral body 10 which firstly has two concentric metal walls / ferrules jointly forming an inter-wall annular space 14 centered on the longitudinal axis 8 of packaging. It is indeed an inner wall / shell 20 centered on the axis 8, and an outer wall / shell 22 also centered on the axis 8.
• the inter-wall space 14 is filled by radiological protection means 18 essentially designed to form a barrier against neutrons emitted by the fuel assemblies housed in the storage device 4.
• radiological protection means 18 are made using a material known per se, such as a matrix composite material polymer, and more specifically whose matrix is a resin, preferably highly hydrogenated, for example of the vinylester resin type.
• This neutron protection material is also known as "resin concrete”. It can also incorporate additives to make the composite material self-extinguishing.
• the means 18 are preferably made in the form of prefabricated blocks distributed in the circumferential direction in the annular space 14, and separated in pairs by thermal conductors 16 contacting each of the two walls 20, 22.
• These conductors 16, made in an alloy having good heat conduction characteristics, of the aluminum alloy or copper type, are specific to the present invention and will now be detailed with reference to FIGS. 2 to 9.
• thermal conductor 16 there is shown a thermal conductor 16 according to a preferred embodiment, this conductor extending preferably over the entire length of the space 14 in the direction of the axis 8, or else alternately cut in the same direction.
• cross section it has the overall shape of an S or Z stretched so that the two projecting angles that it defines are each between 90 and 150 °.
• the conductor firstly has a member 30 for traversing the inter-wall space, this member 30 adopting a substantially planar shape of sufficiently large width to connect the two walls 20, 22 of the lateral packaging body.
• a first member 32 At its end located on the side of the inner wall, the lower end in Figure 2, there is provided a first member 32 for support and connection on the same wall.
• a second member 34 for support and connection to the other wall of the lateral body, namely the outer wall.
• the three members 30, 32, 34 are preferably made in one piece, respectively taking the form of three flat plates, all parallel to the direction of the axis 8, and together defining the two aforesaid projecting angles.
• Each of the support members 32, 34 is intended to be in contact with its associated wall, preferably over its entire surface.
• only the member 32 is also intended to be fixed by screws on the inner wall of the packaging body, with the aid of first fixing points 36, here taking the form of passage holes for the screws. mounting.
• the holes 36 are here preferentially circular, of diameter slightly greater than that of the fixing screws. They are spaced from each other in the direction of the axis 8, even if, possibly, several attachment points can be grouped together by being spaced transversely, that is to say spaced apart from each other in a direction perpendicular to that of the axis 8.
• each of these groups has only two attachment points.
• each segment 32a preferably has a single attachment point 36, or a single group of points in the sense mentioned above, centered on the segment 32a in the longitudinal direction.
• Each slot 40 passes through the entirety of the support and coupling member 32, in order to define independent segments 32a, only connected two by two by a material ligament at the through member through which each slot 40 is prolonged. Indeed, each slot 40 has a first open end at the edge of the member 32, and a closed second end arranged at the passage member 30.
• Each slot 40 thus has a shape of L, arranged in a plane orthogonal to the axis 8.
• the ratio between its width and the length, in the longitudinal direction, of any one of the first two segments 32a arranged on both sides. another of this slot 40 is between 0.005 and 0.1.
• the width of the slot 40 is for example of the order of 2 mm, with a pitch of the order of 100 to 150 mm in the longitudinal direction.
• each slot 40 extends through the through member 30 at a distance that represents 40 to 90% of the total width of the through member in the slot direction, the length of the remaining material ligament. corresponding to 10 to 60% of the total width of this traversing member 30.
• FIG. 3 there is shown a similar conductor, in which the first support and connecting member 32 is intended to be fixed on the outer wall of the side body packing. Therefore, the second support member 34 is here intended to be simply in contact with the inner wall.
• Figures 4 and 5 are derived from that of Figure 2, with a second support member 34 which is shaped similarly to that of the first member 32.
• a second support member 34 which is shaped similarly to that of the first member 32.
• segmentation of the second support member 34 in the longitudinal direction so as to define second segments 34a spaced from each other by second slots 42.
• Each slot 42 passes through the entirety of the support and connecting member 34, to define independent segments 34a, only connected two by two by a material ligament at the through member 30 through which each cleft 42 goes on. Indeed, each slot 42 has a first open end at the edge of the member 34, and a closed second end arranged at the passage member 30.
• each slot 40 has an L shape, arranged in a plane orthogonal to the axis 8, with dimensions and ratios similar to those described for the first slots 40.
• first and second slots 40, 42 are in separate planes, preferably being arranged alternately, with the possibility of providing a plurality of first slots 40 arranged between two second slots 42 directly. consecutive, or vice versa.
• the first and second slots 40, 42 extend sufficiently deep through the through member 30 to provide a lap region 46, when viewed in the direction of the axis 8.
• the traversing member 30 adopts the general shape of a square sinusoidal.
• each segment 34a preferably has a single second attachment point 48, or a single group of points in the above-mentioned sense, centered on the segment 34a in the longitudinal direction.
• thermal conductors 16 follow each other in the circumferential direction in the inter-wall space 14, these conductors preferably being all identical and separated by the presence of the prefabricated neutron protection blocks (not shown). .
• these ends have a rounded shape with a diameter greater than the width of these same slots.
• FIG. 6a shows two welded wall sectors 22a and enclosing the song of the second organ 34.
• the first slots 40 are substantially identical to those of the preceding modes, or even extend to the level of the opposite support member 34, which is not segmented. It is however segmented in the other mode of Figure 7, so as to define second segments 34a spaced from each other by second slots 42 substantially straight.
• Each slot 42 passes through the entire bearing and connecting member 34, in order to define independent segments 34a, only connected two by two by a material ligament at the passage member 30 to through which each slot 42 is extended.
• each slot 42 has a first open end at the edge of the organ 34, and a second closed opposite end arranged at the through member 30.
• the first and second slots 40, 42 are in separate planes, preferably being arranged alternately, with always the possibility of providing several first slots 40 arranged between two second slots 42 directly consecutive, or vice versa.
• the first and second slots 40, 42 extend sufficiently deep through the traversing member 30 to present an overlap area 46, when viewed in the direction of the axis 8.
• thermal conductors 16 in the general form of ⁇ (uppercase omega).
• ⁇ uppercase omega
• first support and connecting members 32 fixed on the inner wall 22
• second support member 34 intended to contact the outer wall of the packaging body
• two 30 directly consecutive passage, connecting the support members 32, 34 the first members 32 could be fixed on the outer wall, and / or it could alternatively be provided two second members 34 and a single first member 32.
• Each conductor 16 of FIG. 8 is then in the form of a conductor as shown in FIG. 4, to which is added another bushing member 30, as well as another first member 32 at the inner radial end. of this other crossing member 30.
• the slots 42 of the second member 34 extend through the new through member 30, so that these slots 42 and each take the general shape of a U through a portion of each of two through members 30, through the second support member 34 which connects them.
• the length of the slot 42 is preferably identical at each of the two crossing members 30.
• first member 32 added is also segmented in a manner analogous to that of the other first member 32, again so as to define segments separated by slots 40 extending into the added through member 30.
• first slots 40 of the two members are located two to two in identical planes orthogonal to the axis 8.
• a longitudinal offset could alternatively be provided between these slots 40, without departing from the scope of the invention.
• the last embodiment shown in FIG. 9 is similar to the one-piece construction of several conductors 16 of the type shown in FIG. 8, with the first slots 40 of the adjacent conductors which would be located in the continuity of each other, which is not necessarily the case in the embodiment of this Figure 8.
• first and second support members 32, 34 which are connected in pairs by traversing members 30.
• Each conductor 16 extends in one piece over an angular sector of the inter-wall annular space, for example over 45 to 180 °.
• each support member 32, 34 is fixed to its respective wall of the lateral body by attachment points 36, 48, even if alternatively, the second members 34 could be in contact only with the outer wall or the wall. internal of the lateral body.
• the corrugated shape defines radially external crests and alternately alternating radially internal crests, which are respectively formed by the second support members 34 and the first support members 32.
• each first and second slot 40, 42 extends in a manner analogous to that of the slots 42 of the embodiment of FIG. 8, namely that it passes through a portion of each of the two bushing members 30. its associated pattern, in addition to the support member connecting these two members 30.
• the slots 40, 42 are thus all U-shaped, and arranged alternately in the longitudinal direction, even if other distributions are possible, such as that shown on each thermal conductor 16 of FIG. 8.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)
• Packages (AREA)
• Installation Of Indoor Wiring (AREA)
• Packaging Of Annular Or Rod-Shaped Articles, Wearing Apparel, Cassettes, Or The Like (AREA)
• Cooling Or The Like Of Electrical Apparatus (AREA)
• Details Of Rigid Or Semi-Rigid Containers (AREA)

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• 2011
  • 2011-12-29 FR FR1162546A patent/FR2985365B1/fr active Active
• 2012
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  • 2012-12-26 EP EP12808832.5A patent/EP2798644B1/fr active Active
  • 2012-12-26 WO PCT/EP2012/076896 patent/WO2013098287A1/fr active Application Filing
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