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
  • G21F5/06—Details of, or accessories to, the containers
  • G21F5/10—Heat-removal systems, e.g. using circulating fluid or cooling fins
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
  • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
  • F28D15/0266—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with separate evaporating and condensing chambers connected by at least one conduit; Loop-type heat pipes; with multiple or common evaporating or condensing chambers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
  • F28D7/0041—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for only one medium being tubes having parts touching each other or tubes assembled in panel form
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S588/00—Hazardous or toxic waste destruction or containment
  • Y10S588/90—Apparatus

Definitions

• the invention relates to an installation intended for ensuring very long-term storage of heat products, capable of emitting
• storage designates a reversible storage of packaged products, accompanied by an evacuation of the heat emitted by these products.
• very long duration means at least fifty years and, preferably, several fifty years.
• a preferred application of the installation according to the invention relates to the storage of very high level and long-lived nuclear waste, such as spent fuel in nuclear reactors.
• the products are packaged in containers and the latter are placed in cavities formed in the ground, said cavities being delimited by concrete walls.
• An air-filled space is provided between each container and the walls of the cavity.
• the heat is evacuated by the only circulation of air, in natural convection.
• a notable disadvantage of such a storage installation is that the cooling is carried out by a primary circuit, in direct contact with the walls of the containers. Such an arrangement is dispersive in the event of an incident, and therefore dangerous for the environment. On the other hand it only allows the evacuation of a very limited heat flux.
• the general arrangement is comparable to the previous one, but the cooling is provided by secondary cooling circuits traversed by a fluid, in particular water, or air in natural convection. These circuits are completely embedded in the concrete walls which delimit the cavities in which the containers are received.
• Such installations have a number of drawbacks. Firstly, since the cooling only takes place inside the concrete walls, the surfaces of these walls delimiting the cavities are heated directly by the stored products. This has the effect of weakening the concrete, at least on the surface. In addition, the temperature of the containers remains very high, which results in rapid aging of their welds. Finally, such a storage installation does not allow the external and therefore internal temperature of the containers to be controlled, which can lead, for example, to the destruction of the spent fuel cladding.
• a third known storage technique differs essentially from the previous one in that the secondary cooling circuits pass through the walls delimiting the cavities and are located partly in the space surrounding the containers.
• Document DD-A-223 562 also discloses an irradiated nuclear fuel storage installation, in which cylindrical containers containing the products are placed one above the other in wells delimited by concrete walls.
• the wall of each well is coated internally with a metal tube which extends above the well to a heat sink, with fins or the like, capable of transmitting the heat which it receives to the surrounding atmosphere.
• a stopper is placed at the top of the well, inside the metal tube, above the containers. The effectiveness of such a device is relatively limited and does not prevent significant heating of the containers and the wall of the well.
• document US-A-4,040,480 proposes a storage facility for radioactive products, in which the products are packaged in cylindrical containers and placed in an annular cavity delimited between the concrete wall of a section well.
• the vertical tube At its upper part, located above a plug closing the well, the vertical tube carries cooling fins in contact with the air.
• the heat diffused by the stored products propagates as well towards the wall of the well as towards the tube forming heat pipe. Relatively rapid damage to the concrete surface is therefore to be expected. In addition, nothing is provided in the event of a heat pipe failure.
• the installations known to date are designed for a maximum service life of about fifty years, while there is a need, in the nuclear industry, for storage of several fifty years , typically up to 300 years.
• the subject of the invention is precisely an installation for storing heat products, such as nuclear waste, which does not have the drawbacks of the installations of the prior art.
• the subject of the invention is a passive storage installation making it possible to evacuate a large amount of heat for a very long time. period, while having a very high reliability and robustness, in particular by subjecting the materials only to stresses compatible with a very long service life.
• this result is obtained by means of a very long-term storage installation for heat products, comprising at least one closed cavity, at least one container for confining said products, capable of being received in the cavity.
• thermosyphon means able to dissipate above the cavity the heat emitted by said products, characterized in that the thermosyphon means are integrated, in part, into a jacket in direct contact with the container it surrounds .
• thermosyphon means integrated into a jacket tightly surrounding the container, ensures efficient evacuation of the heat released by the products received in the container, without risking dispersion of the contamination in the event of an accident.
• the jacket forms a heat shield between the container and the wall of the cavity.
• This generally made of concrete when the products stored are nuclear waste, is thus effectively and homogeneously cooled, in the same way as the container itself. This prevents accelerated aging of the concrete, the welds in the container and the products contained.
• the shirt is removable.
• the cavity is advantageously closed by a removable plug, above the container. This arrangement allows, if necessary, to ensure the replacement of the jacket incorporating the thermosyphon or the removal of the container, in case of problems.
• the shirt is advantageously open and made of a flexible and elastic material such as a metal, so as to be able to occupy a natural state in which it is separated from the container.
• This natural state allows easy assembly and disassembly of the shirt.
• Releasable clamping means are then provided to apply the jacket tightly against the container during storage.
• the jacket then has the shape of an open cylinder along a generator and the releasable clamping means are interposed between the edges facing this generator.
• a space generally filled air is advantageously provided, inside of it, around the container fitted with its jacket, the air possibly or not circulating in natural convection.
• the jacket comprises a plurality of outer tubes filled with heat transfer fluid and the lower and upper ends of which emerge respectively in a lower annular collector and in an upper annular collector.
• cooling fins are preferably formed on at least some of the outer tubes, so as to increase the heat exchange with the air contained in the cavity.
• the outer tubes can be welded to the jacket.
• the jacket may also include a plurality of segments, fixed edge to edge by assembly means such as welds or rivets. Each of the outer tubes is then made in one piece with one of these segments.
• thermosyphon means (generally water) contained in the thermosyphon means, the latter further comprise heat exchange means placed above the cavity and forming a cold source.
• the heat exchange means are connected to the latter by disconnectable connection means.
• the heat exchange means are adapted to variations in the heat flow to be dissipated.
• thermosyphon constitute a heat pipe.
• the installation according to the invention is applied to the storage of nuclear waste.
• the cavity is then delimited by concrete walls.
• FIG. 1 is a vertical sectional view which very schematically shows a storage facility for heat products according to the invention
• Figure 2 is a perspective view, partially cut away and in section, which represents the upper part of the jacket which closely surrounds each container in the installation of Figure 1;
• Figure 3 is a sectional view along a horizontal plane, showing the shirt in solid lines in its natural open state and in phantom when it is tightly tightened on the container;
• FIG. 4 is a sectional view along a horizontal plane illustrating / on a larger scale another embodiment of the shirt; and - Figures 5 and 6 are sectional views comparable to Figure 4, illustrating alternative embodiments of the invention.
• FIG. 1 very schematically represents part of an installation for the very long-term storage of heat products, such as nuclear waste, produced in accordance with the invention.
• the installation comprises at least one closed cavity 10, such as a buried trench, delimited laterally and downwards by concrete walls 12.
• the cavity 10 is in the form of a trench rectilinear buried. This trench is capable of receiving several containers 14 in which the products to be stored are conditioned.
• the shape of the cavity 10 can be different without departing from the scope of the invention.
• each of the containers 14 can be placed in a separate individual cavity.
• the containers 14 used for confining the products to be stored are metal containers, the shape and dimensions of which can be variable, without departing from the scope of the invention.
• the containers 14 are of cylindrical shape and they are placed side by side and on one level in the trench constituting the cavity 10, with their axes oriented substantially vertically. More precisely, each of the containers 14 is in contact neither with the neighboring containers nor with the walls of the cavity 10. In other words, a space 16 filled with air is provided, inside the cavity 10 , around each of the containers 14. The circulation of air in this space 16, by natural convection, contributes to the cooling of the containers 14.
• each of the containers 14 rest on the bottom of the cavity 10 by means of a pedestal 18. Furthermore, positioning or spacing means (not shown) are advantageously provided between the cavity 10 and each of the containers 14, in order to ensure the positioning and the centering of the latter in the cavity.
• the cavity 10 is closed upwards by a concrete slab 20.
• the concrete slab 20 Above each of the containers 14, the concrete slab 20 has a generally circular opening, closed by a removable plug 22 This removable plug 22 is also made of concrete. Its removal makes it possible to set up each of the containers 14 individually in the cavity 10, and optionally to extract them from this cavity.
• handling means (not shown) are provided above the concrete slab 20. This arrangement provides biological protection, when the products stored are nuclear waste, as well as mechanical protection against falls of plane and malicious acts.
• the invention further comprises means 24 forming a thermosyphon ( Figure 2).
• thermosyphon part of these means 24 forming a thermosyphon is integrated into a jacket 26 which surrounds each of the containers 14 so that its smooth inner cylindrical surface 27 is normally in close contact with the smooth outer cylindrical surface 15 of the container.
• the jacket 26 is made of a thermally conductive material, for example a metal such as stainless steel or copper.
• the heat emitted by the products packaged in the containers 14 is transmitted to the means 24 forming a thermosyphon efficiently and homogeneously, over the entire periphery of these containers.
• the thermal connection between the container and the jacket is ensured by the direct contact of the two walls.
• the thermal resistance is reduced, because the effective thickness of the residual air film between the walls is limited to a fraction of a millimeter.
• the part of the means 24 forming a thermosyphon integrated into the jacket 26 is in the form of a closed cooling circuit surrounding the container 14.
• This circuit comprises a plurality of external tubes 28, fixed on the outer surface of the jacket 26 according to the generatrices thereof, and a lower annular collector 30 and an upper annular collector 32, into which the lower and upper ends of the tubes 28 open respectively.
• the tubes 28 are numerous and regularly distributed over the entire circumference of the jacket 26.
• a heat transfer fluid such as water at 100 C, is placed inside the circuit. In operation, the water is in the liquid state in the lower annular collector 30 and in the vapor state in the upper annular collector 32.
• the means 24 forming a thermosyphon thus constitute a heat pipe which tightly surrounds the container while homogenizing the temperature, which avoids the creation of hot spots.
• thermosyphon use the principle of the evaporation / condensation cycle of a heat transfer fluid, for the transfer of heat from a hot source, constituted by the container 14, to a cold source, placed at the above the slab 20. They are waterproof and passive, since they act only by change of phase of the fluid.
• the cold source of the means 24 forming a thermosyphon comprises means 34 of heat exchange, such as an air condenser, installed outside and above the cavity 10, c 'ie above the concrete slab 20.
• These heat exchange means 34 are connected by two pipes 36 to the collectors 30 and 32 of the cooling circuit associated with the jacket 26. More precisely, in the mode described for example, the same heat exchange means 34 is connected to each of the cooling circuits carried by the liners 26 surrounding all the containers 14 placed in the same cavity 10.
• the heat exchange means 34 can take any form, adapted to their function, without departing from the scope of the invention. It should be noted that they can be installed at a certain height above the concrete slab 20 and at a certain distance from the containers, without appreciable degradation of the performance of the installation.
• the pipes 36 which connect the heat exchange means 34 to the lower 30 and upper 32 annular collectors of one or more of the cooling circuits associated with the jackets 26 pass through passages provided for this purpose in the removable plugs 22.
• the sleeves 26 are mounted on the containers 14 so as to be removable independently of the latter. It is thus possible, after removal of any of the removable plugs 22, to replace the jacket 26 of the corresponding container 14 without it being necessary to remove the container from the cavity 10.
• the dimensions of the opening formed in the slab 20 above each of the containers 14 are adapted to allow this replacement.
• This arrangement greatly facilitates the very long-term management of the storage facility. It makes it possible to easily intervene on any element failure of this installation, using remote handling means, placed above the slab 20, ensuring the very long-term evacuation of the heat dissipated by the products stored in the containers.
• the removable nature of the shirts 26 is obtained by making each of them in the form of an open cylinder along a generator.
• the sleeves 26 are formed from a flexible and elastic material having a very low overall stiffness such as a sheet of thin thickness (for example, 3 to 4 mm).
• each of the edges facing the open generator of the jacket 26 comprises a clamping plate 38 oriented radially outwards, so that the two plates 38 are substantially parallel to each other.
• the plates 38 of the same jacket 26 are crossed at regular intervals by holes in which can be mounted with bolts 40 constituting releasable clamping means, capable of applying the jacket 26 tightly against the container 14.
• the bolts 40 constituting here the releasable tightening means can be replaced by any other means making it possible to bring the plates 38 together, in order to apply the smooth cylindrical interior surface 27 of the jacket 26 against the cylindrical exterior surface smooth 15 of the container 14 by deforming the jacket. This result can be obtained without excessive effort, due to the low stiffness of the material in which the jacket 26 is formed.
• the releasable clamping means are preferably chosen so as to be able to be easily installed and actuated by remote handling means, from the space located above the slab 20, after removal of the plug 22 or a shutter provided therein.
• the heat exchange means 34 are advantageously arranged so as to be able to be adapted to a development over time of the heat flow released by the products stored in the containers.
• an intervention on the shirts 26 must be able to be made while these heat exchange means 34 are in place. Consequently, the installation of these heat exchange means 34 above the concrete slab 20 is made so as to allow the replacement of the liners 26, as well as the possible installation and removal of the containers 14.
• connection means 42 which can be disconnected on each of the pipes 36.
• These disconnectable connection means 42 are advantageously located under the slab 20. They are accessible, as are the releasable clamping means, by accesses arranged in the removable plugs 22.
• the disconnectable connection means 42 can take any form without departing from the scope of the invention.
• the jacket 26 is formed from a relatively thin and flexible metal sheet and the tubes 28 are directly welded to the external surface of this sheet.
• the jacket 26 is formed of a plurality of segments 26a, arranged circumferentially end to end one after the other. Each of these segments 26a is fixed to the adjacent segment by assembly means constituted in this case by welds 44.
• each of the outer tubes 28 is made in one piece with a corresponding segment 26a of the jacket 26.
• FIG. 5 illustrates a variant of the embodiment of FIG. 4, which essentially differs by the assembly means connecting edge to edge the different segments 26a forming the jacket 26.
• the segments 26a instead of being connected by welds 44, the segments 26a have superimposed adjacent edges, which pass through fastening members such as rivets shown diagrammatically by phantom lines 44 'in FIG. 5.
• FIG. 6 illustrates another alternative embodiment of the jacket 26. It should be noted that this variant applies equally to the embodiments which have just been described with reference successively to FIGS. 2, 4 and 5, although FIG. 6 represents only the case of FIG. 5.
• each of the outer tubes 28 is provided in this case with at least one cooling fin 46.
• This fin 46 located in the space 16 formed in the cavity 10 around the jacket 26, improves "fin effect" provided by the tubes 28 proper.
• This "fin effect” allows the heat emitted by the products stored in the containers to be removed, in combination with the natural circulation of air in the space 16 surrounding the containers, when this type of cooling becomes sufficient, by case of reduction in time of the heat flux emitted by the stored products.
• the "fin effect” facilitates emergency cooling of the container in the event of failure of the means 24 forming a thermosyphon.
• the storage installation which has just been described makes it possible to ensure the storage, containment and removal of the heat dissipated by calorific products for a very long period.
• the means 24 forming a thermosyphon allow a large amount of heat to be removed, as is necessary at the start of the storage of nuclear waste.
• the proposed arrangement thus makes it possible to maintain the welds of the container 14 and the heat products at a sufficiently low temperature to avoid their accelerated aging. It also makes it possible to subject the surface of the concrete cavity to a homogeneous temperature and sufficiently low to avoid its embrittlement over time.
• thermosyphon constitute a secondary circuit, separated from the products packaged in the container both by the wall of the latter and by the walls of the tubes 28 carried by the jacket 26.
• Environmental protection is thus insured, in the event of a container leak.
• jacket 26 is removable, it is possible to intervene quickly and without danger on the means forming a thermosyphon, directly ensuring the replacement of the defective shirt.
• the invention is not limited to the embodiments which have just been described by way of example, but covers all the variants thereof. So if the storage time is not too long long, the shirts can be tightened and fixed once and for all on the containers. Otherwise, the interchangeable nature of the liners can be obtained by making them in the form of half-shells assembled together in a removable manner, or in the form of half-shells hinged together, or in any other suitable form, ensuring close contact between the liners and the containers, capable of ensuring optimal heat exchange.
• the cooling circuit associated with the jacket can be produced differently, for example in the form of tubes in the form of helices or of passages integrated into regions of greater thickness of the jacket.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Mechanical Engineering (AREA)
• High Energy & Nuclear Physics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)
• Structure Of Emergency Protection For Nuclear Reactors (AREA)
• Drying Of Solid Materials (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Processing Of Solid Wastes (AREA)

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• 1999
  • 1999-03-30 FR FR9903950A patent/FR2791805B1/fr not_active Expired - Fee Related
• 2000
  • 2000-03-23 DE DE60020223T patent/DE60020223T2/de not_active Expired - Lifetime
  • 2000-03-23 JP JP2000610016A patent/JP4324329B2/ja not_active Expired - Fee Related
  • 2000-03-23 WO PCT/FR2000/000735 patent/WO2000060609A1/fr active IP Right Grant
  • 2000-03-23 US US09/937,494 patent/US6802671B1/en not_active Expired - Fee Related
  • 2000-03-23 CN CNB008058377A patent/CN1168100C/zh not_active Expired - Fee Related
  • 2000-03-23 EP EP00914242A patent/EP1166279B1/de not_active Expired - Lifetime
  • 2000-03-23 KR KR1020017012411A patent/KR100735052B1/ko not_active IP Right Cessation
  • 2000-03-23 ES ES00914242T patent/ES2241589T3/es not_active Expired - Lifetime
  • 2000-03-23 CA CA002364950A patent/CA2364950A1/fr not_active Abandoned
  • 2000-03-23 AT AT00914242T patent/ATE295991T1/de not_active IP Right Cessation

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