EP1547097A1 - Container for radioactive materials and method for closing same - Google Patents

Container for radioactive materials and method for closing same

Info

Publication number
EP1547097A1
EP1547097A1 EP03772388A EP03772388A EP1547097A1 EP 1547097 A1 EP1547097 A1 EP 1547097A1 EP 03772388 A EP03772388 A EP 03772388A EP 03772388 A EP03772388 A EP 03772388A EP 1547097 A1 EP1547097 A1 EP 1547097A1
Authority
EP
European Patent Office
Prior art keywords
container
groove
metallic material
cover
main body
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP03772388A
Other languages
German (de)
French (fr)
Inventor
Alain Beziat
Richard Levoy
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique CEA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Commissariat a lEnergie Atomique CEA filed Critical Commissariat a lEnergie Atomique CEA
Publication of EP1547097A1 publication Critical patent/EP1547097A1/en
Withdrawn legal-status Critical Current

Links

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
    • G21F5/06—Details of, or accessories to, the containers
    • G21F5/12—Closures for containers; Sealing arrangements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D19/00—Casting in, on, or around objects which form part of the product
    • B22D19/04—Casting in, on, or around objects which form part of the product for joining parts

Definitions

  • the present invention relates to a container for radioactive materials such as waste or exothermic nuclear materials, the container essentially consisting of a hollow main body inside which are capable of being housed the radioactive materials, as well as a cover intended to close off the hollow main body.
  • the invention also relates to a method for closing such a container.
  • the invention finds a very particular application in the fields of treatment and conditioning of nuclear waste.
  • Containers for radioactive materials are first known, the hollow main body and the cover of which are assembled by welding. If this technique used remains generally satisfactory for containers made of ordinary steels or stainless steels, it is however not suitable for containers made of cast iron, this material being however often retained because of its possibility of being obtained by recycling of very slightly contaminated metallic elements, coming from the dismantling of nuclear installations.
  • welds of small thicknesses namely not exceeding 5 to 6 mm, can be envisaged on cast iron.
  • the conditioning constraints of radioactive materials impose a weld which extends over the full thickness of the container, which is usually between approximately 30 and 130 mm.
  • the welds obtained on thicknesses such as those mentioned above are the seat of significant residual stresses, which can be detrimental to the durability of the container. .
  • the thermal stress relieving treatments carried out during the implementation of methods for conditioning nuclear waste would be difficult to carry out, and not entirely effective on large wall thicknesses of the container.
  • a cast iron container comprising a cover fixed by sealing on the hollow main body, by projection of molten lead in a groove formed by the cover and the body main hollow of this container.
  • the cast lead solidifies in the groove provided for this purpose, and forms a fixing element securing the two main components of the container. Note that the joining of these elements comes essentially from the particular geometry of the groove, having at the level of the hollow main body a lateral surface with two portions inclined relative to the vertical at acute and opposite angles, so as to create an effect of wedge preventing the cover from detaching from the hollow main body.
  • the lead seal obtained is in no way suitable for withstanding high temperatures, and therefore cannot authorize the storage of exothermic nuclear material.
  • the lead melting temperature being only 327 ° C, this value then acts as a limit not to be exceeded to maintain mechanical retention between the two main elements constituting the container, this value even being able to be reduced by because of the sharp drop in the mechanical characteristics of lead beyond a certain temperature.
  • the invention therefore aims to provide a container for radioactive materials comprising a hollow main body and a cover made of at least one first metallic material, the container at least partially overcoming the drawbacks mentioned above relating to the embodiments of the invention. prior art.
  • the object of the invention is to present a container whose mechanical connection and sealing between the cover and the hollow main body are considerably improved compared to the solutions already proposed.
  • the object of the invention is to propose a method for closing such a container.
  • the invention firstly relates to a container for radioactive materials comprising a hollow main body and a cover made of at least one first metallic material, the cover being capable of being fixed to the hollow main body by means of sealing means made of a second metallic material cast in a groove defined by the lid and the hollow main body of the container.
  • the cover and the hollow main body are secured to the sealing means by means of a connection zone, formed by chemical reaction between the first and second metallic materials.
  • the essential characteristic of the invention according to which the second metallic material poured into the groove is capable of reacting chemically with each first metallic material allows the formation of a bonding zone made up of intermetallic compounds ensuring a true tight metallurgical bond between on the one hand the sealing means, and on the other hand the cover and the hollow main body of the container.
  • the reliability of maintaining the lid in a sealed manner on the hollow main body of the container is therefore greatly increased, in particular compared to the solution described in document FR-A-2 733 966.
  • the sealing means provided in this art previous take the form of lead poured into a cast iron groove, the latter having a specific geometry ensuring the maintenance of the cover on the hollow main body, when the lead is solidified in the groove.
  • no chemical reaction occurs between lead and cast iron due to the nonexistence of iron-lead intermetallic compounds, this property thus prohibiting the presence of this type of compound at the interface between sealing means and the groove.
  • each first metallic material is of the cast iron or steel type.
  • the second metallic material can be a cast iron, zinc or one of its alloys, steel, or even aluminum or one of its alloys.
  • the bonding zone can then be made of alloys of the iron-carbon, iron-zinc or iron-aluminum type, these materials being capable of ensuring perfect mechanical resistance between the sealing means and the two main container components.
  • the metallic materials indicated above, capable of being used to produce the sealing means advantageously have a higher melting temperature than that of lead used in the prior art, and are therefore able to bear the presence of exothermic radioactive materials inside the container.
  • the value of this temperature nevertheless advantageously makes it possible to envisage a reopening of the relatively easy cover, using conventional means capable of causing the sealing means to merge.
  • connection zone has an average thickness of between approximately 10 ⁇ m and 5 mm, so that the mechanical connection generated between the cover and the hollow main body of the container is durably resistant and waterproof.
  • the cover has an external lateral surface partially defining the groove and comprising two adjacent portions inclined respectively by an angle ⁇ and by an angle ⁇ relative to a direction parallel to a main longitudinal axis of the container, the angles ⁇ and ⁇ being acute and opposite in order to obtain a wedge effect.
  • the invention also relates to a method of closing a container for radioactive materials comprising a hollow main body and a cover made of at least one first metallic material, the method comprising a step of placing place the cover on the body main hollow of the container so as to form a groove between these two elements, followed by a step of producing sealing means ensuring the fixing of the cover to the hollow main body of the container by pouring a second metallic material into the groove.
  • the second metallic material is chosen so that it is capable of reacting chemically with each first metallic material, so as to form a bonding zone between on the one hand the sealing means, and on the other hand the lid and the hollow main body of the container.
  • the step of fitting the cover is followed by a step of preheating the first material constituting the groove, this last step can also be preceded by a preparation of the surfaces of the groove.
  • the step of producing the sealing means is preceded by a step of excessively casting the second metallic material into the groove for a determined period, so as to cause heating of the first metallic material. constituting the groove, as well as washing the surfaces of this groove.
  • the step of producing the sealing means by casting the second metallic material in the groove is followed by a step of heating this second material resting in the groove, in order to promote the chemical reaction between the first and second metallic materials.
  • Figure 1 shows a partial schematic sectional view of an upper portion of a container for radioactive materials, according to a preferred embodiment of the invention, and before the sealing means have been put in place
  • Figure 2 shows a partial schematic sectional view of an upper portion of the container shown in Figure 1, after solidification of the sealing means in the groove
  • Figure 3 shows a schematic perspective view of a particular arrangement, for performing the step of making the sealing means for the method of closing a container according to the invention.
  • FIG. 1 there is shown partially and schematically a container 1 for radioactive materials, according to a preferred embodiment of the present invention.
  • the container 1 comprises a hollow main body 2, defining a space 4 inside which can be housed the radioactive materials, such as exothermic nuclear waste.
  • the container 1 has a cover 6 capable of being fitted into the hollow main body 2, so as to obtain a space 4 completely closed.
  • the space 4, preferably of circular section, is delimited on the one hand with the aid of a lateral surface 8 and a bottom (not shown) formed by the hollow main body 2, and on the other hand at l using an upper surface 10 formed by the cover 6, the latter as well as the hollow main body 2 being arranged coaxially.
  • the hollow main body 2 and the cover 6 respectively have annular contact surfaces 12 and 14, allowing the stop in translation of the cover 6 relative to the hollow main body 2, when the interlocking of these two elements 2 and 6.
  • the contact surfaces 12 and 14 are preferably designed so that the cover 6 can be housed in the hollow main body 2 without protruding outside of it, and that their respective upper surfaces 13 and 15 lie substantially in the same plane perpendicular to a longitudinal main axis (not shown in these figures) of the container 1.
  • the clearance 16 can be of the order of 0.5 mm.
  • the container 1 in which the container 1 is shown while the cover 6 has not yet been fixed on the hollow main body 2, the latter has an inner lateral surface 20 in its upper portion, while that the cover 6 has an outer side surface 22.
  • the adjacent and continuous side surfaces 20 and 22 form a groove 24 preferably extending all around the axis main longitudinal section of the container 1 along a variable horizontal section, this groove 24 being open to the outside of this container 1. It is specified that the groove 24 could naturally extend only partially around the main longitudinal axis of the container 1, for example to form portions of angularly spaced grooves, without departing from the scope of the invention.
  • the groove 24 can also be produced so as to have a constant horizontal section, the shape of this groove being easily modular, by simple adaptation of the internal lateral surface 20 and the external lateral surface 22.
  • the groove 24 thus obtained makes it possible to offer a space in which sealing means 26
  • the cover 6 and the hollow main body 2 on the one hand, and the sealing means 26 on the other part are separated by a connecting zone 28, having a shape substantially identical to that of the wall of the groove 24 initially provided, over a thickness 29 which can range from 10 ⁇ m to 5 mm, and preferably being of the order of 2 mm.
  • connection zone 28 located substantially at the initial location of the external lateral surface 22 and the internal lateral surface 20, results from a chemical reaction produced between the cover 6 and the hollow main body 2 on the one hand, and the sealing means 26 on the other hand, during the casting of the sealing means 26 in the groove 24.
  • the connection zone 28 provides a rigid mechanical connection between the sealing means 26 and the two main elements 2 and 6 of the container 1, this specific feature of the invention ensuring perfect sealing of the container.
  • the hollow main body 2 and the cover 6 are made from at least one first metallic material, and preferably from the same material such as steel or cast iron.
  • the sealing means 26 are made of a second metallic material, such as cast iron, zinc or one of its alloys, steel, aluminum or one of its alloys, or still any other metallic material capable of exhibiting reactivity with the first metallic material retained, in order to chemically react with the latter and to constitute a bonding zone 28 comprising intermetallic compounds.
  • the cover 6 and the hollow main body 2 are made of steel and the sealing means 26 are made of cast iron, these two materials are capable of reacting with each other when the cast iron is still liquid, so as to form a bonding zone 28 composed of an iron-carbon alloy, obtained by diffusion of the carbon from the cast iron to the steel.
  • the bonding zone 28 has a carbon gradient in a direction going from the sealing means 26 towards the cover 6 or the hollow main body 2 of the container 1, and the structure of this connection zone 28 evolves from a mixture of ferrite and perlite to a cast iron, passing through a structure of eutectoid steel then hyper-eutectoid .
  • connection zones 28 obtained are respectively composed of an iron-zinc alloy and an iron-alloy aluminum, ensuring rigid mechanical maintenance between the sealing means 26 and the two main elements 2 and 6 of the container 1.
  • connection zone 28 had a structure similar to that which can be observed in the case of galvanizing operations carried out by quenching steel elements in liquid zinc.
  • first and second materials are made of steel, these then being chosen so that carbon diffusion is possible when the sealing means 26 are in the liquid state, in order to obtain a connection zone 28 of iron-carbon alloy having a carbon gradient in a direction going from the sealing means 26 towards the cover 6 or the hollow main body 2 of the container 1.
  • the external lateral surface 22 of the cover 6 may comprise two adjacent portions 30 and 32 inclined respectively by an angle ⁇ and by an angle ⁇ relative to a direction 34 parallel to the main longitudinal axis of the container 1, the angles ⁇ and ⁇ being acute and opposite in order to obtain a wedge effect when it is desired to extract the cover 6 from the hollow main body 2.
  • the upper portion 32 is inclined so as to approach the main longitudinal axis away from the upper portion of the container 1, while the lower portion 30 is inclined so as to approach the main longitudinal axis in s' moving towards a lower portion of the container 1.
  • the inner lateral surface 20 of the hollow main body 2 can also include a portion 36 inclined in the same way as the upper portion 32 of the outer lateral surface 22, namely so as to approach the main axis. longitudinal away from the upper portion of the container 1, this portion 36 preferably being opposite the upper portion 32 of the outer lateral surface 22.
  • the sealing means 26 take place in the groove 24, the part of these sealing means 26 located between the portions 32 and 36 initially provided, takes substantially the form of a cap providing additional mechanical retention of the cover 6 on the hollow main body 2.
  • the shape of the groove 24 can be designed in any other way aimed at providing a geometry ensuring maintenance of the cover 6 on the hollow main body 2, when the sealing means 26 are solidified inside this initially planned groove 24, without departing from the scope of the invention.
  • the groove 24 has a variable width, which can for example extend between 10 and 20 mm, and being of the order of 15 mm at the portions 32 and 36 opposite.
  • the invention also relates to a container closure method, such as that which has just been described above.
  • the first metallic material chosen to make the cover 6 and the hollow main body 2 is steel, for example of the E24 type, while that the second cast metallic material used to form the sealing means 26 is a cast iron, for example of the EN-GJS-400-15 type.
  • the first step in this process consists in placing the cover 6 on the hollow main body 2 of the container 1, so as to form the groove 24, as can be seen in FIG. 1.
  • the surfaces 20 and 22 can be prepared using a mechanical technique such as sandblasting, a chemical technique such as degreasing or pickling, an electrochemical technique or a deposit of a layer of metallic material such as zinc or nickel.
  • the surfaces 20 and 22 of the groove 24 can be nickel-plated in order to avoid oxidation of these surfaces during their rise in temperature and in the presence of air.
  • the possible techniques for depositing the layer of metallic material are taken from the conventional metallic deposition techniques, such as that of galvanization for the deposition of zinc.
  • the step of preparing the surfaces 20 and 22 of the groove 24 can consist of the combination of several of the techniques mentioned above.
  • these surfaces 20 and 22 of the groove 24 can then undergo a step of preheating at low temperature to avoid their oxidation, for example of the order of 400 ° C., using collars electric heaters or any other means ensuring such a function. Note that this operation can be carried out under neutral gas to completely avoid the harmful effects that an oxidation of the surfaces 20 and 22 of the groove 24 could cause. Then, the cast iron is poured into the groove 24, so as to form the sealing means 26 shown in FIG. 2.
  • means for casting the iron 40 assembled on the cover 6 of the container 1, comprise a container 42 in which the iron is located in the liquid state.
  • the container 42 is pivotally mounted on a support 44 secured to the end of an arm 46, the latter being able to pivot around the main longitudinal axis 38 of the container 1.
  • the liquid cast iron resting in the container is capable of being poured into an orifice taking the form of a funnel 48, also mounted on the arm 46 of the means 40.
  • the funnel 48 then communicates with a discharge duct 50, of which the end 52 is oriented close to and facing the groove 24.
  • the funnel 48 is moreover capable of pivoting along an axis parallel to the axis of rotation between the container 42 and the support 44, this specificity being provided to ensure a clean discharge of the liquid iron into the funnel 48, regardless of the quantity of iron present in the container 42.
  • the rotations of the elements 42 and 48 relative to the support 44 can be performed manually, using handles 54 and 56 respectively.
  • the end 52 of the iron discharge duct 50 can describe a circular movement allowing it to be constantly facing the bottom of the groove 24, this characteristic specific then ensuring the possibility of taking advantage of a uniform distribution of the cast iron inside this groove 24, during the implementation of the casting operation.
  • the pig iron is then poured into the groove 24, for example at a temperature of around 1470 ° C.
  • the casting of the cast iron is carried out by putting the arm 46 of the means 40 in rotation about the main longitudinal axis 38, either manually or automatically.
  • the cast iron can be poured in excess and continuously, in order to heat and wash the surfaces 20 and 22 of the groove 24, previously nickel-plated.
  • a system for recovering excess cast iron can then consist of means for discharging the cast iron located at the bottom of the groove 24, or alternatively in means arranged on the surface for recovering the cast iron overflowing from this groove.
  • the excess casting period can in particular be determined as a function of the optimum temperature to be reached for the surfaces 20 and 22 of the groove 24, therefore taking into account various parameters such as the surface area of these surfaces 20 and 22, the flow rate iron, iron temperature, etc. Furthermore, it is noted that this period may also depend on the thickness of the metal deposit previously made on the surfaces 20 and 22 of the groove 2.
  • the filling time is approximately 40 seconds and the quantity of excess cast iron for washing and heating is of the order of 250 kg, or a washing rate of 0.06 kg / s. cm 2 .
  • a final step consists in heating the cast iron so that it remains liquid in the groove 24.
  • This step has main objective of promoting the diffusion of carbon from the melting of the sealing means 26, to the steel of the hollow main body 2 and of the cover 6 of the container 1. The diffusion of carbon then makes it possible to obtain a connection zone 28 in iron-carbon alloy, ensuring a mechanical connection and sealed, directly between the sealing means 26 on the one hand, and the hollow main body 2 and the cover 6 on the other.
  • This step of heating the cast iron in the groove 24 can be carried out using conventional heating means such as electric heating collars (not shown), at a temperature of the order of 500 ° C. for approximately 2 hours. . It is specified that the heating time can be adapted so that the chemical reaction between the first and second metallic materials is completed, or so that the bonding zone 28 is large enough to generate a perfect tight mechanical bond. between the cover 6 and the hollow main body 2 of the container 1.
  • connection zone 28 obtained following the implementation of such a method, has a microstructure evolving over a thickness 29 of approximately 2 mm, from a mixture from ferrite and perlite to a cast iron, passing through a eutectoid then hyper-eutectoid steel structure.
  • the bonding zone 28 had a breaking strength of approximately 276 MPa, for an elastic limit of 146 MPa at 0.2%, and an elongation at break of the '' around 33.1%.
  • the surfaces 20 and 22 of the groove 24 do not undergo preparation by metallic deposition such as nickel, but are pickled so as to obtain surfaces 20 and 22 capable of reacting easily with the cast zinc.
  • connection zone 28 is composed of an iron-zinc alloy, substantially identical to that obtained during a galvanization carried out by quenching steel parts in liquid zinc.
  • the use of zinc or one of its alloys as second metallic material is advantageous in the sense that the reopening of the cover 6 can easily be envisaged by melting sealing means 26, due to the low melting temperature of this type of material.
  • the steps are similar to those described previously in the first two preferred embodiments, with the difference that the casting step is preferably carried out under protection of a neutral gas.
  • the reopening of the cover 6 sealed on the hollow main body 2 of the container 1 can easily be carried out by fusion of the sealing means 26.
  • This fusion is preferably carried out using a torch heating. , laser, induction or resistors.

Abstract

The invention concerns a container (1) for radioactive materials comprising a main hollow body (2) and a lid (6) made of at least one first metallic material, the lid being adapted to be fixed on the main hollow body via sealing means (26) made of a second metallic material cast in a groove (24) defined by the lid and the main hollow body of the container. The invention is characterized in that the lid (6) and the main hollow body (2) are secured to the sealing means (26) through a linking zone (28), formed by chemical reaction between the first and second metallic materials. The invention also concerns a method for closing such a container (1).

Description

CONTENEUR POUR MATIERES RADIOACTIVES ET PROCEDE DE FERMETURE D'UN TEL CONTENEUR CONTAINER FOR RADIOACTIVE MATERIALS AND METHOD FOR CLOSING SUCH A CONTAINER
DESCRIPTIONDESCRIPTION
DOMAINE TECHNIQUE La présente invention se rapporte à un conteneur pour matières radioactives telles que des déchets ou des matières nucléaires exothermiques, le conteneur étant essentiellement constitué d'un corps principal creux à l'intérieur duquel sont aptes à être logées les matières radioactives, ainsi que d'un couvercle destiné à obturer le corps principal creux.TECHNICAL FIELD The present invention relates to a container for radioactive materials such as waste or exothermic nuclear materials, the container essentially consisting of a hollow main body inside which are capable of being housed the radioactive materials, as well as a cover intended to close off the hollow main body.
Par ailleurs, l'invention se rapporte également à un procédé de fermeture d'un tel conteneur. L'invention trouve une application toute particulière dans les domaines du traitement et du conditionnement de déchets nucléaires.Furthermore, the invention also relates to a method for closing such a container. The invention finds a very particular application in the fields of treatment and conditioning of nuclear waste.
ETAT DE LA TECHNIQUE ANTERIEURESTATE OF THE PRIOR ART
Dans ce domaine technique, plusieurs réalisations ont déjà été proposées. On connaît tout d'abord des conteneurs pour matières radioactives dont le corps principal creux et le couvercle sont assemblés par soudage. Si cette technique employée reste globalement satisfaisante pour des conteneurs réalisés en aciers ordinaires ou en aciers inoxydables, elle n'est cependant pas adaptée à des conteneurs réalisés en fonte, ce matériau étant pourtant souvent retenu en raison sa possibilité d'être obtenu par recyclage d'éléments métalliques très faiblement contaminés, provenant du démantèlement d'installations nucléaires.In this technical field, several achievements have already been proposed. Containers for radioactive materials are first known, the hollow main body and the cover of which are assembled by welding. If this technique used remains generally satisfactory for containers made of ordinary steels or stainless steels, it is however not suitable for containers made of cast iron, this material being however often retained because of its possibility of being obtained by recycling of very slightly contaminated metallic elements, coming from the dismantling of nuclear installations.
En effet, seules des soudures de faibles épaisseurs, à savoir ne dépassant pas 5 à 6 mm, peuvent être envisagées sur de la fonte. Or de manière générale, les contraintes de conditionnement de matières radioactives imposent une soudure qui s'étend sur la pleine épaisseur du conteneur, qui est habituellement comprise entre environ 30 et 130 mm.In fact, only welds of small thicknesses, namely not exceeding 5 to 6 mm, can be envisaged on cast iron. However, in general, the conditioning constraints of radioactive materials impose a weld which extends over the full thickness of the container, which is usually between approximately 30 and 130 mm.
Par ailleurs, même dans le cas où le soudage est réalisé sur des matériaux réputés être de bonne soudabilité, les soudures obtenues sur des épaisseurs telles que celles mentionnées ci-dessus sont le siège de contraintes résiduelles importantes, pouvant être préjudiciables à la durabilité du conteneur. Dans un tel cas, les traitements thermiques de détensionnement opérés lors de la mise en œuvre de procédés de conditionnement de déchets nucléaires seraient difficilement réalisables, et pas totalement efficaces sur des fortes épaisseurs de paroi du conteneur. Dans l'art antérieur, il a également été proposé d'interposer un joint métallique entre le couvercle et le corps principal creux assemblés par boulonnage, le joint étant conçu de façon à présenter des caractéristiques techniques satisfaisantes pendant une durée limitée, de l'ordre de quelques dizaines d'années. Néanmoins, outre l'existence d'une contrainte de limitation dans le temps d'un tel joint métallique, cette solution s'avère peu performante lorsque le conteneur est entreposé dans un environnement corrosif. En effet, l'épaisseur de matière disponible à l'avancée du front de corrosion est faible, et réduit considérablement la période durant laquelle une étanchéité acceptable est conservée entre le couvercle et le corps principal creux du conteneur.Furthermore, even in the case where the welding is carried out on materials reputed to be of good weldability, the welds obtained on thicknesses such as those mentioned above are the seat of significant residual stresses, which can be detrimental to the durability of the container. . In such a case, the thermal stress relieving treatments carried out during the implementation of methods for conditioning nuclear waste would be difficult to carry out, and not entirely effective on large wall thicknesses of the container. In the prior art, it has also been proposed to interpose a metal seal between the cover and the hollow main body assembled by bolting, the seal being designed so as to have satisfactory technical characteristics for a limited period, of the order of a few decades. However, in addition to the existence of a constraint time limitation of such a metal seal, this solution is not very effective when the container is stored in a corrosive environment. Indeed, the thickness of material available at the advance of the corrosion front is small, and considerably reduces the period during which an acceptable seal is maintained between the cover and the hollow main body of the container.
Pour remédier aux inconvénients cités ci- dessus, il a enfin été proposé, par le demandeur, un conteneur en fonte comportant un couvercle fixé par scellement sur le corps principal creux, par projection de plomb fondu dans une rainure formée par le couvercle et le corps principal creux de ce conteneur. Lors de la mise en œuvre d'une telle technique décrite dans le document FR-A-2 733 966, le plomb coulé se solidifie dans la rainure prévue à cet effet, et forme un élément de fixation solidarisant les deux composants principaux du conteneur. Notons que la solidarisâtion de ces éléments provient essentiellement de la géométrie particulière de la rainure, présentant au niveau du corps principal creux une surface latérale à deux portions inclinées par rapport à la verticale selon des angles aigus et opposés, de manière à créer un effet de coin empêchant le couvercle de se désolidariser du corps principal creux.To remedy the drawbacks mentioned above, it has finally been proposed by the applicant, a cast iron container comprising a cover fixed by sealing on the hollow main body, by projection of molten lead in a groove formed by the cover and the body main hollow of this container. During the implementation of such a technique described in the document FR-A-2 733 966, the cast lead solidifies in the groove provided for this purpose, and forms a fixing element securing the two main components of the container. Note that the joining of these elements comes essentially from the particular geometry of the groove, having at the level of the hollow main body a lateral surface with two portions inclined relative to the vertical at acute and opposite angles, so as to create an effect of wedge preventing the cover from detaching from the hollow main body.
Cependant, il a été remarqué qu'avec un tel agencement, la liaison mécanique obtenue entre le couvercle et le corps principal creux du conteneur n'était pas totalement satisfaisante, provoquant ainsi des incertitudes quant à la présence d'une étanchéité parfaite entre ces deux éléments, et par conséquent des doutes concernant la présence d'une isolation sûre des matières radioactives à l'intérieur du conteneur.However, it has been noted that with such an arrangement, the mechanical connection obtained between the cover and the hollow main body of the container was not completely satisfactory, thus causing uncertainties as to the presence of a seal. perfect between these two elements, and therefore doubts about the presence of a safe isolation of radioactive materials inside the container.
De plus, le joint en plomb obtenu n'est en aucun cas adapté pour supporter des températures élevées, et ne peut par conséquent pas autoriser le stockage de matières nucléaires exothermiques. En effet, le température de fusion du plomb n'étant que de 327°C, cette valeur fait alors office de limite à ne pas dépasser pour conserver un maintien mécanique entre les deux éléments principaux constituant le conteneur, cette valeur pouvant même être réduite en raison de la forte baisse des caractéristiques mécaniques du plomb au-delà d'une certaine température.In addition, the lead seal obtained is in no way suitable for withstanding high temperatures, and therefore cannot authorize the storage of exothermic nuclear material. Indeed, the lead melting temperature being only 327 ° C, this value then acts as a limit not to be exceeded to maintain mechanical retention between the two main elements constituting the container, this value even being able to be reduced by because of the sharp drop in the mechanical characteristics of lead beyond a certain temperature.
EXPOSÉ DE L'INVENTIONSTATEMENT OF THE INVENTION
L'invention a donc pour but de proposer un conteneur pour matières radioactives comprenant un corps principal creux ainsi qu'un couvercle réalisés dans au moins un premier matériau métallique, le conteneur remédiant au moins partiellement aux inconvénients mentionnés ci-dessus relatifs aux réalisations de l'art antérieur.The invention therefore aims to provide a container for radioactive materials comprising a hollow main body and a cover made of at least one first metallic material, the container at least partially overcoming the drawbacks mentioned above relating to the embodiments of the invention. prior art.
Plus précisément, le but de l'invention est de présenter un conteneur dont la liaison mécanique et 1' étanchéité entre le couvercle et le corps principal creux sont considérablement améliorées par rapport aux solutions déjà proposées.More specifically, the object of the invention is to present a container whose mechanical connection and sealing between the cover and the hollow main body are considerably improved compared to the solutions already proposed.
Par ailleurs, le but de l'invention est de proposer un procédé de fermeture d'un tel conteneur. Pour ce faire, l'invention a tout d'abord pour objet un conteneur pour matières radioactives comprenant un corps principal creux ainsi qu'un couvercle réalisés dans au moins un premier matériau métallique, le couvercle étant susceptible d'être fixé sur le corps principal creux par l'intermédiaire de moyens de scellement réalisés dans un second matériau métallique coulé dans une rainure définie par le couvercle et le corps principal creux du conteneur. Selon l'invention, le couvercle et le corps principal creux sont solidarisés aux moyens de scellement à l'aide d'une zone de liaison, formée par réaction chimique entre les premier et second matériaux métalliques.Furthermore, the object of the invention is to propose a method for closing such a container. To do this, the invention firstly relates to a container for radioactive materials comprising a hollow main body and a cover made of at least one first metallic material, the cover being capable of being fixed to the hollow main body by means of sealing means made of a second metallic material cast in a groove defined by the lid and the hollow main body of the container. According to the invention, the cover and the hollow main body are secured to the sealing means by means of a connection zone, formed by chemical reaction between the first and second metallic materials.
Avantageusement, la caractéristique essentielle de l'invention selon laquelle le second matériau métallique coulé dans la rainure est capable de réagir chimiquement avec chaque premier matériau métallique, permet la formation d'une zone de liaison constituée de composés intermétalliques assurant une véritable liaison métallurgique étanche entre d'une part les moyens de scellement, et d'autre part le couvercle et le corps principal creux du conteneur.Advantageously, the essential characteristic of the invention according to which the second metallic material poured into the groove is capable of reacting chemically with each first metallic material, allows the formation of a bonding zone made up of intermetallic compounds ensuring a true tight metallurgical bond between on the one hand the sealing means, and on the other hand the cover and the hollow main body of the container.
La fiabilité du maintien de façon étanche du couvercle sur le corps principal creux du conteneur est donc largement augmentée, notamment par rapport à la solution décrite dans le document FR-A-2 733 966. En effet, les moyens de scellement prévus dans cet art antérieur prennent la forme de plomb coulé dans une rainure en fonte, cette dernière disposant d'une géométrie spécifique assurant le maintien du couvercle sur le corps principal creux, lorsque le plomb est solidifié dans la rainure. Or, contrairement au conteneur selon l'invention, aucune réaction chimique ne se produit entre le plomb et la fonte en raison de l'inexistence de composés intermétalliques fer-plomb, cette propriété interdisant ainsi la présence de ce type de composés au niveau de l'interface entre les moyens de scellement et la rainure. Par conséquent, aucune liaison métallurgique rigide n'étant prévue entre d'une part les moyens de scellement et d'autre part le couvercle et le corps principal creux du conteneur, la liaison obtenue entre le couvercle et le corps principal creux n'est pas en mesure d'autoriser une résistance mécanique acceptable, ni même une étanchéité durable entre ces deux éléments principaux du conteneur. Préférentiellement , chaque premier matériau métallique est du type fonte ou acier. De cette façon, le second matériau métallique peut être une fonte, du zinc ou l'un de ses alliages, de l'acier, ou encore de l'aluminium ou l'un de ses alliages. Dans de tels cas, la zone de liaison peut alors être constituée d'alliages du type fer-carbone, fer-zinc ou fer-aluminium, ces matériaux étant capables d'assurer une parfaite résistance mécanique entre les moyens de scellement et les deux principaux éléments constitutifs du conteneur.The reliability of maintaining the lid in a sealed manner on the hollow main body of the container is therefore greatly increased, in particular compared to the solution described in document FR-A-2 733 966. Indeed, the sealing means provided in this art previous take the form of lead poured into a cast iron groove, the latter having a specific geometry ensuring the maintenance of the cover on the hollow main body, when the lead is solidified in the groove. Unlike the container according to the invention, no chemical reaction occurs between lead and cast iron due to the nonexistence of iron-lead intermetallic compounds, this property thus prohibiting the presence of this type of compound at the interface between sealing means and the groove. Consequently, since no rigid metallurgical connection is provided between on the one hand the sealing means and on the other hand the cover and the hollow main body of the container, the connection obtained between the cover and the hollow main body is not able to allow an acceptable mechanical resistance, or even a lasting seal between these two main elements of the container. Preferably, each first metallic material is of the cast iron or steel type. In this way, the second metallic material can be a cast iron, zinc or one of its alloys, steel, or even aluminum or one of its alloys. In such cases, the bonding zone can then be made of alloys of the iron-carbon, iron-zinc or iron-aluminum type, these materials being capable of ensuring perfect mechanical resistance between the sealing means and the two main container components.
Par ailleurs, il est précisé que les matériaux métalliques indiqués ci-dessus, susceptibles d'être employés pour réaliser les moyens de scellement, disposent avantageusement d'une température de fusion plus élevée que celle du plomb utilisé dans l'art antérieur, et sont par conséquent capables de supporter la présence de matières radioactives exothermiques à l'intérieur du conteneur. De plus, il est également précisé que même si certains matériaux comme le zinc et ses alliages disposent d'une température de fusion suffisamment élevée pour autoriser le stockage de matières radioactives exothermiques, la valeur de cette température permet néanmoins avantageusement d'envisager une réouverture du couvercle relativement aisée, à l'aide de moyens classiques susceptibles de provoquer la fusion des moyens de scellement.Furthermore, it is specified that the metallic materials indicated above, capable of being used to produce the sealing means, advantageously have a higher melting temperature than that of lead used in the prior art, and are therefore able to bear the presence of exothermic radioactive materials inside the container. In addition, it is also specified that even if certain materials such as zinc and its alloys have a sufficiently high melting temperature to allow the storage of exothermic radioactive materials, the value of this temperature nevertheless advantageously makes it possible to envisage a reopening of the relatively easy cover, using conventional means capable of causing the sealing means to merge.
Selon un mode de réalisation préféré de la présente invention, la zone de liaison dispose d'une épaisseur moyenne comprise entre environ 10 μm et 5 mm, de sorte que la liaison mécanique engendrée entre le couvercle et le corps principal creux du conteneur est durablement résistante et étanche.According to a preferred embodiment of the present invention, the connection zone has an average thickness of between approximately 10 μm and 5 mm, so that the mechanical connection generated between the cover and the hollow main body of the container is durably resistant and waterproof.
Pour accroître encore davantage cette liaison, il est possible de prévoir que le couvercle comporte une surface latérale extérieure définissant partiellement la rainure et comprenant deux portions adjacentes inclinées respectivement d'un angle α et d'un angle β par rapport à une direction parallèle à un axe principal longitudinal du conteneur, les angles α et β étant aigus et opposés afin d'obtenir un effet de coin.To further increase this connection, it is possible to provide that the cover has an external lateral surface partially defining the groove and comprising two adjacent portions inclined respectively by an angle α and by an angle β relative to a direction parallel to a main longitudinal axis of the container, the angles α and β being acute and opposite in order to obtain a wedge effect.
D'autre part, l'invention a également pour objet un procédé de fermeture d'un conteneur pour matières radioactives comprenant un corps principal creux ainsi qu'un couvercle réalisés dans au moins un premier matériau métallique, le procédé comportant une étape de mise en place du couvercle sur le corps principal creux du conteneur de manière à former une rainure entre ces deux éléments, suivie d'une étape de réalisation de moyens de scellement assurant la fixation du couvercle sur le corps principal creux du conteneur en coulant un second matériau métallique dans la rainure. Selon l'invention, on choisit le second matériau métallique de sorte qu'il soit apte à réagir chimiquement avec chaque premier matériau métallique, de manière à former une zone de liaison entre d'une part les moyens de scellement, et d'autre part le couvercle et le corps principal creux du conteneur.On the other hand, the invention also relates to a method of closing a container for radioactive materials comprising a hollow main body and a cover made of at least one first metallic material, the method comprising a step of placing place the cover on the body main hollow of the container so as to form a groove between these two elements, followed by a step of producing sealing means ensuring the fixing of the cover to the hollow main body of the container by pouring a second metallic material into the groove. According to the invention, the second metallic material is chosen so that it is capable of reacting chemically with each first metallic material, so as to form a bonding zone between on the one hand the sealing means, and on the other hand the lid and the hollow main body of the container.
De manière préférentielle, l'étape de mise en place du couvercle est suivie d'une étape de préchauffage du premier matériau constituant la rainure, cette dernière étape pouvant également être précédée d'une préparation des surfaces de la rainure.Preferably, the step of fitting the cover is followed by a step of preheating the first material constituting the groove, this last step can also be preceded by a preparation of the surfaces of the groove.
De plus, il est possible de prévoir que l'étape de réalisation des moyens de scellement est précédée d'une étape de coulée en excès du second matériau métallique dans la rainure pendant une période déterminée, de manière à provoquer un chauffage du premier matériau métallique constituant la rainure, ainsi qu'un lavage des surfaces de cette rainure.In addition, it is possible to provide that the step of producing the sealing means is preceded by a step of excessively casting the second metallic material into the groove for a determined period, so as to cause heating of the first metallic material. constituting the groove, as well as washing the surfaces of this groove.
Préférentiellement, l'étape de réalisation des moyens de scellement par coulée du second matériau métallique dans la rainure est suivie d'une étape de chauffage de ce second matériau reposant dans la rainure, afin de favoriser la réaction chimique entre les premier et second matériaux métalliques. D'autres avantages et caractéristiques de l'invention apparaîtront dans la description détaillée non limitative ci-dessous.Preferably, the step of producing the sealing means by casting the second metallic material in the groove is followed by a step of heating this second material resting in the groove, in order to promote the chemical reaction between the first and second metallic materials. . Other advantages and characteristics of the invention will appear in the detailed non-limiting description below.
BRÈVE DESCRIPTION DES DESSINS Cette description sera faite au regard des dessins annexés parmi lesquels ; la figure 1 représente une vue schématique partielle en coupe d'une portion supérieure d'un conteneur pour matières radioactives, selon un mode de réalisation préféré de l'invention, et avant que les moyens de scellement aient été mis en place, la figure 2 représente une vue schématique partielle en coupe d'une portion supérieure du conteneur représenté sur la figure 1, après solidification des moyens de scellement dans la rainure, et la figure 3 représente une vue schématique en perspective d'un agencement particulier, permettant d'effectuer l'étape de réalisation des moyens de scellement du procédé de fermeture d'un conteneur selon l'invention.BRIEF DESCRIPTION OF THE DRAWINGS This description will be made with reference to the accompanying drawings, among which; Figure 1 shows a partial schematic sectional view of an upper portion of a container for radioactive materials, according to a preferred embodiment of the invention, and before the sealing means have been put in place, Figure 2 shows a partial schematic sectional view of an upper portion of the container shown in Figure 1, after solidification of the sealing means in the groove, and Figure 3 shows a schematic perspective view of a particular arrangement, for performing the step of making the sealing means for the method of closing a container according to the invention.
EXPOSE DÉTAILLÉ DE MODES DE RÉALISATION PRÉFÉRÉSDETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
En référence aux figures 1 et 2, il est représenté partiellement et schématiquement un conteneur 1 pour matières radioactives, selon un mode de réalisation préféré de la présente invention.Referring to Figures 1 and 2, there is shown partially and schematically a container 1 for radioactive materials, according to a preferred embodiment of the present invention.
Sur ces figures, seule une partie de la portion supérieure du conteneur 1 est visible, ce conteneur 1 étant de forme sensiblement cylindrique de section circulaire, mais pouvant bien entendu adopter toute autre forme compatible avec le domaine technique considéré .In these figures, only a part of the upper portion of the container 1 is visible, this container 1 being of substantially cylindrical shape of circular section, but which can of course be adopted any other form compatible with the technical field considered.
Le conteneur 1 comprend un corps principal creux 2, définissant un espace 4 à l'intérieur duquel peuvent être logées les matières radioactives, telles que des déchets nucléaires exothermiques. De plus, le conteneur 1 comporte un couvercle 6 susceptible d'être emboîté dans le corps principal creux 2, de manière à obtenir un espace 4 totalement fermé. L'espace 4, préférentiellement de section circulaire, est délimité d'une part à l'aide d'une surface latérale 8 et d'un fond (non représenté) formés par le corps principal creux 2, et d'autre part à l'aide d'une surface supérieure 10 formée par le couvercle 6, ce dernier ainsi que le corps principal creux 2 étant disposés de façon coaxiale.The container 1 comprises a hollow main body 2, defining a space 4 inside which can be housed the radioactive materials, such as exothermic nuclear waste. In addition, the container 1 has a cover 6 capable of being fitted into the hollow main body 2, so as to obtain a space 4 completely closed. The space 4, preferably of circular section, is delimited on the one hand with the aid of a lateral surface 8 and a bottom (not shown) formed by the hollow main body 2, and on the other hand at l using an upper surface 10 formed by the cover 6, the latter as well as the hollow main body 2 being arranged coaxially.
Comme ceci est visible sur les figures 1 et 2, le corps principal creux 2 et le couvercle 6 disposent respectivement de surfaces de contact annulaires 12 et 14, permettant l'arrêt en translation du couvercle 6 par rapport au corps principal creux 2, lors de l'emboîtement de ces deux éléments 2 et 6. Par ailleurs, les surfaces de contact 12 et 14 sont de préférence conçues afin que le couvercle 6 puisse être logé dans le corps principal creux 2 sans faire saillie en dehors de celui-ci, et que leurs surfaces supérieures respectives 13 et 15 se situent sensiblement dans un même plan perpendiculaire à un axe principal longitudinal (non représenté sur ces figures) du conteneur 1. Bien entendu, il est possible de prévoir un jeu 16 entre la surface latérale 8 de l'espace 4 et un cylindre 18 constituant la partie inférieure du couvercle 6, de manière à faciliter l'introduction de ce couvercle 6 dans le corps principal creux 2 du conteneur 1. A titre d'exemple, le jeu 16 peut être de 1 ' ordre de 0,5 mm.As can be seen in FIGS. 1 and 2, the hollow main body 2 and the cover 6 respectively have annular contact surfaces 12 and 14, allowing the stop in translation of the cover 6 relative to the hollow main body 2, when the interlocking of these two elements 2 and 6. Furthermore, the contact surfaces 12 and 14 are preferably designed so that the cover 6 can be housed in the hollow main body 2 without protruding outside of it, and that their respective upper surfaces 13 and 15 lie substantially in the same plane perpendicular to a longitudinal main axis (not shown in these figures) of the container 1. Of course, it is possible to provide a clearance 16 between the lateral surface 8 of the space 4 and a cylinder 18 constituting the lower part of the cover 6, so as to facilitate the introduction of this cover 6 into the hollow main body 2 of the container 1. As an example, the clearance 16 can be of the order of 0.5 mm.
Plus spécifiquement en référence à la figure 1, sur laquelle le conteneur 1 est représenté alors que le couvercle 6 n'a pas encore été fixé sur le corps principal creux 2, celui-ci présente dans sa portion supérieure une surface latérale intérieure 20, tandis que le couvercle 6 présente une surface latérale extérieure 22. Lorsque le couvercle 6 est mis en place sur le corps principal creux 2, les surfaces latérales 20 et 22 adjacentes et continues forment une rainure 24 s'étendant de préférence tout autour de l'axe principal longitudinal du conteneur 1 selon une section horizontale variable, cette rainure 24 étant ouverte sur l'extérieur de ce conteneur 1. Il est précisé que la rainure 24 pourrait naturellement s'étendre que partiellement autour de l'axe principal longitudinal du conteneur 1, par exemple pour former des portions de rainures espacées angulairement, sans sortir du cadre de l'invention. Au même titre, notons que la rainure 24 peut également être réalisée de façon à disposer d'une section horizontale constante, la forme de cette rainure étant facilement modulable, par simple adaptation de la surface latérale intérieure 20 et de la surface latérale extérieure 22. La rainure 24 ainsi obtenue permet d'offrir un espace dans lequel des moyens de scellement 26More specifically with reference to FIG. 1, in which the container 1 is shown while the cover 6 has not yet been fixed on the hollow main body 2, the latter has an inner lateral surface 20 in its upper portion, while that the cover 6 has an outer side surface 22. When the cover 6 is placed on the hollow main body 2, the adjacent and continuous side surfaces 20 and 22 form a groove 24 preferably extending all around the axis main longitudinal section of the container 1 along a variable horizontal section, this groove 24 being open to the outside of this container 1. It is specified that the groove 24 could naturally extend only partially around the main longitudinal axis of the container 1, for example to form portions of angularly spaced grooves, without departing from the scope of the invention. In the same way, it should be noted that the groove 24 can also be produced so as to have a constant horizontal section, the shape of this groove being easily modular, by simple adaptation of the internal lateral surface 20 and the external lateral surface 22. The groove 24 thus obtained makes it possible to offer a space in which sealing means 26
(représentés sur la figure 2) vont permettre la fixation par scellement du couvercle 6 sur le corps principal creux 2 du conteneur 1.(represented in FIG. 2) will allow the fixing by sealing of the cover 6 on the hollow main body 2 of the container 1.
En référence à la figure 2, sur laquelle le conteneur 1 est représenté dans un état fermé et fixé, on voit que les moyens de scellement 26, préalablement coulés dans la rainure 24 prévue initialement entre le couvercle 6 et le corps principal creux 2, ont été introduits dans cette rainure 24 de manière à occuper l'intégralité de l'espace défini par cette rainure. Par ailleurs, lorsque les moyens de scellement 26 sont dans un état solidifié tel que celui représenté sur la figure 2, les surfaces 20 et 22 de la rainure 24 ne sont plus apparentes (mais tout de même schématisées en pointillés afin de faciliter la compréhension) , et les moyens de scellement 26 ne sont plus en contact direct avec le couvercle 6 et le corps principal creux 2. En effet, le couvercle 6 et le corps principal creux 2 d'une part, et les moyens de scellement 26 d'autre part, sont séparés par une zone de liaison 28, disposant d'une forme sensiblement identique à celle de la paroi de la rainure 24 initialement prévue, sur une épaisseur 29 pouvant aller de 10 μm à 5 mm, et étant de préférence de l'ordre de 2 mm.Referring to Figure 2, in which the container 1 is shown in a closed and fixed state, it can be seen that the sealing means 26, previously cast in the groove 24 initially provided between the cover 6 and the hollow main body 2, have been introduced into this groove 24 so as to occupy the entire space defined by this groove. Furthermore, when the sealing means 26 are in a solidified state such as that shown in FIG. 2, the surfaces 20 and 22 of the groove 24 are no longer apparent (but all the same schematized in dotted lines in order to facilitate understanding) , and the sealing means 26 are no longer in direct contact with the cover 6 and the hollow main body 2. In fact, the cover 6 and the hollow main body 2 on the one hand, and the sealing means 26 on the other part, are separated by a connecting zone 28, having a shape substantially identical to that of the wall of the groove 24 initially provided, over a thickness 29 which can range from 10 μm to 5 mm, and preferably being of the order of 2 mm.
La zone de liaison 28, située sensiblement à l'emplacement initial de la surface latérale extérieure 22 et de la surface latérale intérieure 20, résulte d'une réaction chimique produite entre le couvercle 6 et le corps principal creux 2 d'une part, et les moyens de scellement 26 d'autre part, lors de la coulée des moyens de scellement 26 dans la rainure 24. De cette façon, la zone de liaison 28 assure une liaison mécanique rigide entre les moyens de scellement 26 et les deux principaux éléments 2 et 6 du conteneur 1, cette spécificité de l'invention assurant une étanchéité parfaite du conteneur.The connection zone 28, located substantially at the initial location of the external lateral surface 22 and the internal lateral surface 20, results from a chemical reaction produced between the cover 6 and the hollow main body 2 on the one hand, and the sealing means 26 on the other hand, during the casting of the sealing means 26 in the groove 24. In this way, the connection zone 28 provides a rigid mechanical connection between the sealing means 26 and the two main elements 2 and 6 of the container 1, this specific feature of the invention ensuring perfect sealing of the container.
Afin d'obtenir la zone de liaison 28 par réaction chimique, le corps principal creux 2 et le couvercle 6 sont réalisés dans au moins un premier matériau métallique, et de préférence dans le même matériau tel que l'acier ou une fonte. Par ailleurs, les moyens de scellement 26 sont réalisés dans un second matériau métallique, tel qu'une fonte, du zinc ou l'un de ses alliages, de l'acier, de l'aluminium ou l'un de ses alliages, ou encore tout autre matériau métallique susceptible de présenter une réactivité avec le premier matériau métallique retenu, afin de réagir chimiquement avec ce dernier et de constituer une zone de liaison 28 comportant des composés intermétalliques.In order to obtain the connection zone 28 by chemical reaction, the hollow main body 2 and the cover 6 are made from at least one first metallic material, and preferably from the same material such as steel or cast iron. Furthermore, the sealing means 26 are made of a second metallic material, such as cast iron, zinc or one of its alloys, steel, aluminum or one of its alloys, or still any other metallic material capable of exhibiting reactivity with the first metallic material retained, in order to chemically react with the latter and to constitute a bonding zone 28 comprising intermetallic compounds.
Ainsi, à titre d'exemple non limitatif, lorsque le couvercle 6 et le corps principal creux 2 sont en acier et que les moyens de scellement 26 sont en fonte, ces deux matériaux sont aptes à réagir l'un avec l'autre lorsque la fonte est encore liquide, de manière à former une zone de liaison 28 composée d'un alliage fer-carbone, obtenu par diffusion du carbone de la fonte vers l'acier. Une fois la réaction chimique terminée et les moyens de scellement 26 solidifiés, la zone de liaison 28 présente un gradient de carbone dans une direction allant des moyens de scellement 26 vers le couvercle 6 ou le corps principal creux 2 du conteneur 1, et la structure de cette zone de liaison 28 évolue depuis un mélange de ferrite et de perlite jusqu'à une fonte, en passant par une structure d'acier eutectoïde puis hyper-eutectoide .Thus, by way of nonlimiting example, when the cover 6 and the hollow main body 2 are made of steel and the sealing means 26 are made of cast iron, these two materials are capable of reacting with each other when the cast iron is still liquid, so as to form a bonding zone 28 composed of an iron-carbon alloy, obtained by diffusion of the carbon from the cast iron to the steel. Once the chemical reaction has ended and the sealing means 26 have solidified, the bonding zone 28 has a carbon gradient in a direction going from the sealing means 26 towards the cover 6 or the hollow main body 2 of the container 1, and the structure of this connection zone 28 evolves from a mixture of ferrite and perlite to a cast iron, passing through a structure of eutectoid steel then hyper-eutectoid .
De la même manière et toujours à titre d'exemple, lorsque les moyens de scellement 26 comportent du zinc ou de l'aluminium, les zones de liaison 28 obtenues sont respectivement composées d'un alliage fer-zinc et d'un alliage fer-aluminium, assurant le maintien mécanique rigide entre les moyens de scellement 26 et le deux éléments principaux 2 et 6 du conteneur 1. De plus, dans le cas de l'utilisation de zinc ou de l'un de ses alliages, il a été remarqué que la zone de liaison 28 disposait d'une structure similaire à celle pouvant être observée dans le cas d'opérations de galvanisation réalisées par trempe d'éléments en acier dans du zinc liquide.In the same way and still by way of example, when the sealing means 26 comprise zinc or aluminum, the connection zones 28 obtained are respectively composed of an iron-zinc alloy and an iron-alloy aluminum, ensuring rigid mechanical maintenance between the sealing means 26 and the two main elements 2 and 6 of the container 1. In addition, in the case of the use of zinc or one of its alloys, it has been observed that the connection zone 28 had a structure similar to that which can be observed in the case of galvanizing operations carried out by quenching steel elements in liquid zinc.
Enfin, un dernier exemple concerne le cas où les premier et second matériaux sont en acier, ceux- ci étant alors choisis de manière à ce qu'une diffusion de carbone soit possible lorsque les moyens de scellement 26 sont à l'état liquide, afin d'obtenir une zone de liaison 28 en alliage fer-carbone présentant un gradient de carbone dans une direction allant des moyens de scellement 26 vers le couvercle 6 ou le corps principal creux 2 du conteneur 1.Finally, a last example concerns the case where the first and second materials are made of steel, these then being chosen so that carbon diffusion is possible when the sealing means 26 are in the liquid state, in order to obtain a connection zone 28 of iron-carbon alloy having a carbon gradient in a direction going from the sealing means 26 towards the cover 6 or the hollow main body 2 of the container 1.
Afin de renforcer encore davantage la fixation du couvercle 6 sur le corps principal creux 2 du conteneur 1, il est possible d'adapter la géométrie initiale de la rainure 24, formée par la surface latérale intérieure 20 et la surface latérale extérieure 22.In order to further strengthen the fixing of the cover 6 on the hollow main body 2 of the container 1, it is possible to adapt the initial geometry of the groove 24, formed by the surface internal lateral surface 20 and the external lateral surface 22.
A cet effet, en référence à la figure 1, la surface latérale extérieure 22 du couvercle 6 peut comprendre deux portions 30 et 32 adjacentes inclinées respectivement d'un angle α et d'un angle β par rapport à une direction 34 parallèle à l'axe principal longitudinal du conteneur 1, les angles α et β étant aigus et opposés afin d'obtenir un effet de coin lorsque l'on désire extraire le couvercle 6 du corps principal creux 2. Comme on peut le voir sur la figure 1, la portion supérieure 32 est inclinée de manière à se rapprocher de l'axe principal longitudinal en s 'éloignant vers la portion supérieure du conteneur 1, tandis que la portion inférieure 30 est inclinée de manière à se rapprocher de l'axe principal longitudinal en s 'éloignant vers une portion inférieure du conteneur 1.To this end, with reference to FIG. 1, the external lateral surface 22 of the cover 6 may comprise two adjacent portions 30 and 32 inclined respectively by an angle α and by an angle β relative to a direction 34 parallel to the main longitudinal axis of the container 1, the angles α and β being acute and opposite in order to obtain a wedge effect when it is desired to extract the cover 6 from the hollow main body 2. As can be seen in FIG. 1, the upper portion 32 is inclined so as to approach the main longitudinal axis away from the upper portion of the container 1, while the lower portion 30 is inclined so as to approach the main longitudinal axis in s' moving towards a lower portion of the container 1.
De plus, notons que la surface latérale intérieure 20 du corps principal creux 2 peut également comprendre une portion 36 inclinée de la même façon que la portion supérieure 32 de la surface latérale extérieure 22, à savoir de manière à se rapprocher de l'axe principal longitudinal en s 'éloignant vers la portion supérieure du conteneur 1, cette portion 36 étant de préférence en regard de la portion supérieure 32 de la surface latérale extérieure 22. Ainsi, lorsque les moyens de scellement 26 prennent place dans la rainure 24, la partie de ces moyens de scellement 26 se trouvant entre les portions 32 et 36 initialement prévues, prend sensiblement la forme d'une calotte assurant un maintien mécanique supplémentaire du couvercle 6 sur le corps principal creux 2. Naturellement, la forme de la rainure 24 peut être conçue de toute autre manière visant à prévoir une géométrie assurant un maintien du couvercle 6 sur le corps principal creux 2 , lorsque les moyens de scellement 26 sont solidifiés à l'intérieur de cette rainure 24 initialement prévue, sans sortir du cadre de 1' invention. Enfin, notons que la rainure 24 dispose d'une largeur variable, pouvant par exemple s'étendre entre 10 et 20 mm, et étant de l'ordre de 15 mm au niveau des portions 32 et 36 en regard.In addition, note that the inner lateral surface 20 of the hollow main body 2 can also include a portion 36 inclined in the same way as the upper portion 32 of the outer lateral surface 22, namely so as to approach the main axis. longitudinal away from the upper portion of the container 1, this portion 36 preferably being opposite the upper portion 32 of the outer lateral surface 22. Thus, when the sealing means 26 take place in the groove 24, the part of these sealing means 26 located between the portions 32 and 36 initially provided, takes substantially the form of a cap providing additional mechanical retention of the cover 6 on the hollow main body 2. Naturally, the shape of the groove 24 can be designed in any other way aimed at providing a geometry ensuring maintenance of the cover 6 on the hollow main body 2, when the sealing means 26 are solidified inside this initially planned groove 24, without departing from the scope of the invention. Finally, note that the groove 24 has a variable width, which can for example extend between 10 and 20 mm, and being of the order of 15 mm at the portions 32 and 36 opposite.
L'invention concerne également un procédé de fermeture de conteneur, tel que celui qui vient d'être décrit ci-dessus.The invention also relates to a container closure method, such as that which has just been described above.
Selon un premier mode de réalisation préféré du procédé selon l'invention qui va être décrit ci-dessous, le premier matériau métallique choisi pour réaliser le couvercle 6 et le corps principal creux 2 est de l'acier, par exemple du type E24, tandis que le second matériau métallique coulé employé pour former les moyens de scellement 26 est une fonte, par exemple du type EN-GJS-400-15. La première étape de ce procédé consiste à mettre en place le couvercle 6 sur le corps principal creux 2 du conteneur 1, de manière à former la rainure 24, comme cela est visible sur la figure 1.According to a first preferred embodiment of the method according to the invention which will be described below, the first metallic material chosen to make the cover 6 and the hollow main body 2 is steel, for example of the E24 type, while that the second cast metallic material used to form the sealing means 26 is a cast iron, for example of the EN-GJS-400-15 type. The first step in this process consists in placing the cover 6 on the hollow main body 2 of the container 1, so as to form the groove 24, as can be seen in FIG. 1.
Lors de la réalisation de ce procédé, il est ensuite préférable d'effectuer une étape de préparation des surfaces de la rainure 24, à savoir la surface latérale intérieure 20 du corps principal creux 2 et la surface latérale extérieure 22 du couvercle 6.When carrying out this process, it is then preferable to carry out a step of preparing the surfaces of the groove 24, namely the inner side surface 20 of the hollow main body 2 and the outer side surface 22 of the cover 6.
Pour ce faire, plusieurs solutions sont envisageables. On peut en effet préparer les surfaces 20 et 22 à l'aide d'une technique mécanique telle que le sablage, d'une technique chimique telle que le dégraissage ou le décapage, d'une technique électrochimique ou encore d'un dépôt d'une couche de matériau métallique tel que le zinc ou le nickel. A titre d'exemple, les surfaces 20 et 22 de la rainure 24 peuvent être nickelées afin d'éviter l'oxydation de ces surfaces lors de leur montée en température et en présence d'air. Par ailleurs, les techniques possibles pour déposer la couche de matériau métallique sont prises parmi les techniques classiques de dépôt métallique, comme celle de galvanisation pour le dépôt de zinc. Bien entendu, l'étape de préparation des surfaces 20 et 22 de la rainure 24 peut consister en la combinaison de plusieurs des techniques mentionnées ci- dessus.To do this, several solutions are possible. We can indeed prepare the surfaces 20 and 22 using a mechanical technique such as sandblasting, a chemical technique such as degreasing or pickling, an electrochemical technique or a deposit of a layer of metallic material such as zinc or nickel. For example, the surfaces 20 and 22 of the groove 24 can be nickel-plated in order to avoid oxidation of these surfaces during their rise in temperature and in the presence of air. Furthermore, the possible techniques for depositing the layer of metallic material are taken from the conventional metallic deposition techniques, such as that of galvanization for the deposition of zinc. Of course, the step of preparing the surfaces 20 and 22 of the groove 24 can consist of the combination of several of the techniques mentioned above.
La préparation des surfaces 20 et 22 de la rainure 24 achevée, ces surfaces 20 et 22 peuvent alors subir une étape de préchauffage à basse température pour éviter leur oxydation, par exemple de l'ordre de 400°C, à l'aide de colliers chauffants électriques ou de tout autre moyen assurant une telle fonction. Notons que cette opération peut être effectuée sous gaz neutre pour éviter totalement les effets néfastes que pourrait provoquer une oxydation des surfaces 20 et 22 de la rainure 24. Ensuite, il est procédé à la coulée de la fonte dans la rainure 24, de manière à former les moyens de scellement 26 représentés sur la figure 2.The preparation of the surfaces 20 and 22 of the groove 24 completed, these surfaces 20 and 22 can then undergo a step of preheating at low temperature to avoid their oxidation, for example of the order of 400 ° C., using collars electric heaters or any other means ensuring such a function. Note that this operation can be carried out under neutral gas to completely avoid the harmful effects that an oxidation of the surfaces 20 and 22 of the groove 24 could cause. Then, the cast iron is poured into the groove 24, so as to form the sealing means 26 shown in FIG. 2.
En référence à la figure 3, il est représenté un agencement possible pour réaliser la coulée du second matériau métallique dans la rainureReferring to Figure 3, there is shown a possible arrangement for making the casting of the second metallic material in the groove
24, cette dernière étant annulaire d'axe identique à l'axe principal longitudinal 38 du conteneur 1.24, the latter being annular with an axis identical to the main longitudinal axis 38 of the container 1.
Comme on peut 1 ' apercevoir sur cette figure, des moyens de coulée de la fonte 40, assemblés sur le couvercle 6 du conteneur 1, comprennent un récipient 42 dans lequel est située la fonte à l'état liquide. Le récipient 42 est monté de façon pivotante sur un support 44 solidaire de l'extrémité d'un bras 46, ce dernier étant apte à pivoter autour de l'axe principal longitudinal 38 du conteneur 1.As can be seen in this figure, means for casting the iron 40, assembled on the cover 6 of the container 1, comprise a container 42 in which the iron is located in the liquid state. The container 42 is pivotally mounted on a support 44 secured to the end of an arm 46, the latter being able to pivot around the main longitudinal axis 38 of the container 1.
La fonte liquide reposant dans le récipient est susceptible d'être déversée dans un orifice prenant la forme d'un entonnoir 48, également monté sur le bras 46 des moyens 40. L'entonnoir 48 communique alors avec un conduit d'évacuation 50, dont l'extrémité 52 est orientée à proximité et en regard de la rainure 24. Notons que l'entonnoir 48 est par ailleurs apte à pivoter selon un axe parallèle à l'axe de rotation entre le récipient 42 et le support 44, cette spécificité étant prévue afin d'assurer un déversement propre de la fonte liquide dans l'entonnoir 48, quelle que soit la quantité de fonte présente dans le récipient 42. D'autre part, les rotations des éléments 42 et 48 par rapport au support 44 peuvent être réalisées manuellement, respectivement à l'aide de poignées 54 et 56.The liquid cast iron resting in the container is capable of being poured into an orifice taking the form of a funnel 48, also mounted on the arm 46 of the means 40. The funnel 48 then communicates with a discharge duct 50, of which the end 52 is oriented close to and facing the groove 24. Note that the funnel 48 is moreover capable of pivoting along an axis parallel to the axis of rotation between the container 42 and the support 44, this specificity being provided to ensure a clean discharge of the liquid iron into the funnel 48, regardless of the quantity of iron present in the container 42. On the other hand, the rotations of the elements 42 and 48 relative to the support 44 can be performed manually, using handles 54 and 56 respectively.
Ainsi, en faisant pivoter le bras 46 tout autour de l'axe 38, l'extrémité 52 du conduit d'évacuation de fonte 50 peut décrire un mouvement circulaire lui permettant d'être constamment en regard du fond de la rainure 24, cette caractéristique spécifique assurant alors la possibilité de se prévaloir d'une répartition uniforme de la fonte à l'intérieur de cette rainure 24, lors de la mise en œuvre de l'opération de coulée.Thus, by pivoting the arm 46 all around the axis 38, the end 52 of the iron discharge duct 50 can describe a circular movement allowing it to be constantly facing the bottom of the groove 24, this characteristic specific then ensuring the possibility of taking advantage of a uniform distribution of the cast iron inside this groove 24, during the implementation of the casting operation.
Dans ce premier mode de réalisation préféré du procédé selon l'invention, la fonte est ensuite coulée dans la rainure 24, par exemple à une température avoisinant 1470°C. Comme cela vient d'être indiqué, la coulée de la fonte s'effectue en mettant le bras 46 des moyens 40 en rotation autour de l'axe principal longitudinal 38, indifféremment de façon manuelle ou automatique. Avant que la coulée réalisée ne soit directement destinée à former les moyens de scellement 26, la fonte peut être coulée en excès et en continue, afin de chauffer et laver les surfaces 20 et 22 de la rainure 24, préalablement nickelées. Un système de récupération de la fonte excédentaire (non représenté) peut alors consister en des moyens d'évacuation de la fonte situés en bas de la rainure 24, ou encore en des moyens agencés en surface pour récupérer la fonte débordante de cette rainure . La coulée de fonte en excès pendant une période déterminée permet ainsi d'éliminer les impuretés présentes dans la rainure 24, et de dissoudre rapidement la couche de nickel déposée sur les surfaces 20 et 22, dans le but d'obtenir des surfaces en acier 20 et 22 propres autorisant une bonne réaction chimique avec la fonte. La période de coulée en excès peut notamment être déterminée en fonction de la température optimale à atteindre pour les surfaces 20 et 22 de la rainure 24, donc en tenant compte de paramètres divers tels que de la superficie de ces surfaces 20 et 22, du débit de fonte, de la température de la fonte, etc. Par ailleurs, il est noté que cette période peut aussi dépendre de l'épaisseur du dépôt métallique préalablement effectué sur les surfaces 20 et 22 de la rainure 2 . Typiquement, pour une surface totale de la rainure 24 d'environ 400 cm2, le temps de remplissage est d'environ 40 secondes et la quantité de fonte coulée en excès pour le lavage et le chauffage est de l'ordre de 250 kg, soit un débit de lavage de 0,06 kg/s. cm2.In this first preferred embodiment of the method according to the invention, the pig iron is then poured into the groove 24, for example at a temperature of around 1470 ° C. As has just been indicated, the casting of the cast iron is carried out by putting the arm 46 of the means 40 in rotation about the main longitudinal axis 38, either manually or automatically. Before the casting carried out is directly intended to form the sealing means 26, the cast iron can be poured in excess and continuously, in order to heat and wash the surfaces 20 and 22 of the groove 24, previously nickel-plated. A system for recovering excess cast iron (not shown) can then consist of means for discharging the cast iron located at the bottom of the groove 24, or alternatively in means arranged on the surface for recovering the cast iron overflowing from this groove. Pouring excess cast iron for a specified period thus eliminates the impurities present in the groove 24, and quickly dissolve the nickel layer deposited on the surfaces 20 and 22, in order to obtain clean steel surfaces 20 and 22 allowing a good chemical reaction with the cast iron. The excess casting period can in particular be determined as a function of the optimum temperature to be reached for the surfaces 20 and 22 of the groove 24, therefore taking into account various parameters such as the surface area of these surfaces 20 and 22, the flow rate iron, iron temperature, etc. Furthermore, it is noted that this period may also depend on the thickness of the metal deposit previously made on the surfaces 20 and 22 of the groove 2. Typically, for a total surface of the groove 24 of approximately 400 cm 2 , the filling time is approximately 40 seconds and the quantity of excess cast iron for washing and heating is of the order of 250 kg, or a washing rate of 0.06 kg / s. cm 2 .
Lorsque les moyens de scellement sont coulés dans la rainure 24 et que les opérations de chauffage et de lavage de cette rainure 24 sont achevées, une étape ultime consiste à chauffer la fonte de sorte qu'elle reste liquide dans la rainure 24. Cette étape a pour principal objectif de favoriser la diffusion du carbone depuis la fonte des moyens de scellement 26, vers l'acier du corps principal creux 2 et du couvercle 6 du conteneur 1. La diffusion de carbone permet alors d'obtenir une zone de liaison 28 en alliage fer-carbone, assurant une liaison mécanique et étanche, directement entre les moyens de scellement 26 d'une part, et le corps principal creux 2 et le couvercle 6 d'autre part.When the sealing means are poured into the groove 24 and the heating and washing operations of this groove 24 are completed, a final step consists in heating the cast iron so that it remains liquid in the groove 24. This step has main objective of promoting the diffusion of carbon from the melting of the sealing means 26, to the steel of the hollow main body 2 and of the cover 6 of the container 1. The diffusion of carbon then makes it possible to obtain a connection zone 28 in iron-carbon alloy, ensuring a mechanical connection and sealed, directly between the sealing means 26 on the one hand, and the hollow main body 2 and the cover 6 on the other.
Cette étape de chauffage de la fonte dans la rainure 24 peut s'effectuer à l'aide de moyens de chauffage classiques tels que des colliers chauffants électriques (non représentés) , à une température de l'ordre de 500°C pendant environ 2 heures. Il est précisé que la durée de chauffage peut être adaptée de manière à ce que la réaction chimique entre les premier et second matériaux métalliques soit terminée, ou de façon à ce que la zone de liaison 28 soit suffisamment importante pour engendrer une parfaite liaison mécanique étanche entre le couvercle 6 et le corps principal creux 2 du conteneur 1.This step of heating the cast iron in the groove 24 can be carried out using conventional heating means such as electric heating collars (not shown), at a temperature of the order of 500 ° C. for approximately 2 hours. . It is specified that the heating time can be adapted so that the chemical reaction between the first and second metallic materials is completed, or so that the bonding zone 28 is large enough to generate a perfect tight mechanical bond. between the cover 6 and the hollow main body 2 of the container 1.
Comme mentionné ci-dessus dans la description du conteneur 1, la zone de liaison 28, obtenue suite à la mise en œuvre d'un tel procédé, dispose d'une microstructure évoluant sur une épaisseur 29 d'environ 2 mm, depuis un mélange de ferrite et de perlite jusqu'à une fonte, en passant par une structure d'acier eutectoide puis hyper-eutectoïde .As mentioned above in the description of the container 1, the connection zone 28, obtained following the implementation of such a method, has a microstructure evolving over a thickness 29 of approximately 2 mm, from a mixture from ferrite and perlite to a cast iron, passing through a eutectoid then hyper-eutectoid steel structure.
Des tests ont alors démontré que la zone de liaison 28 disposait d'une résistance à la rupture d'environ 276 MPa, pour une limite d'élasticité de 146 MPa à 0,2%, et d'un allongement à la rupture de l'ordre de 33,1%.Tests then demonstrated that the bonding zone 28 had a breaking strength of approximately 276 MPa, for an elastic limit of 146 MPa at 0.2%, and an elongation at break of the '' around 33.1%.
Dans un second mode de réalisation préféré du procédé selon l'invention, lorsque le second matériau métallique est choisit parmi le zinc et ses alliages et que le premier matériau métallique reste de l'acier, les surfaces 20 et 22 de la rainure 24 ne subissent pas de préparation par dépôt métallique comme le nickel, mais sont décapées de manière à obtenir des surfaces 20 et 22 susceptibles de réagir facilement avec le zinc coulé.In a second preferred embodiment of the method according to the invention, when the second metallic material is chosen from zinc and its alloys and the first metallic material remains the steel, the surfaces 20 and 22 of the groove 24 do not undergo preparation by metallic deposition such as nickel, but are pickled so as to obtain surfaces 20 and 22 capable of reacting easily with the cast zinc.
Les autres étapes du procédé sont réalisées sensiblement de la même façon que celles mentionnées dans le premier mode de réalisation préféré de l'invention, à la différence que le zinc est coulé aux alentours de 470°C, et que le chauffage post-coulée est maintenu à 500°C pendant 4 heures.The other steps of the process are carried out in substantially the same way as those mentioned in the first preferred embodiment of the invention, with the difference that the zinc is cast at around 470 ° C., and that the post-cast heating is maintained at 500 ° C for 4 hours.
Après solidification du second matériau métallique, la zone de liaison 28 est composée d'un alliage fer-zinc, sensiblement identique à celui obtenu lors d'une galvanisation réalisée par trempe de pièces en acier dans du zinc liquide.After solidification of the second metallic material, the connection zone 28 is composed of an iron-zinc alloy, substantially identical to that obtained during a galvanization carried out by quenching steel parts in liquid zinc.
En outre, de façon générale, quel que soit le premier matériau métallique retenu, l'emploi du zinc ou de l'un de ses alliages comme second matériau métallique est avantageux en ce sens que la réouverture du couvercle 6 peut être facilement envisagée par fusion des moyens de scellement 26, en raison de la faible température de fusion de ce type de matériau.In addition, in general, whatever the first metallic material selected, the use of zinc or one of its alloys as second metallic material is advantageous in the sense that the reopening of the cover 6 can easily be envisaged by melting sealing means 26, due to the low melting temperature of this type of material.
Selon un troisième mode de réalisation préféré du procédé selon l'invention, lorsque le second matériau métallique est choisit parmi l'aluminium et ses alliages et que le premier matériau métallique reste de l'acier, les étapes sont similaires à celles décrites précédemment dans les deux premiers modes de réalisation préférés, à la différence que l'étape de coulée est préférentiellement effectuée sous protection d'un gaz neutre. Ces conditions opératoires spécifiques permettant de travailler à l'abri de l'atmosphère oxydante, interdisent par conséquent la formation d'une couche d'alumine sur les surfaces 20 et 22 de la rainure 24, qui serait fortement préjudiciable à la réaction chimique entre le fer et l'aluminium, et donc aux performances mécaniques de la zone de liaison 28.According to a third preferred embodiment of the method according to the invention, when the second metallic material is chosen from aluminum and its alloys and the first metallic material remains steel, the steps are similar to those described previously in the first two preferred embodiments, with the difference that the casting step is preferably carried out under protection of a neutral gas. These specific operating conditions making it possible to work away from the oxidizing atmosphere, consequently prohibit the formation of an alumina layer on the surfaces 20 and 22 of the groove 24, which would be highly detrimental to the chemical reaction between the iron and aluminum, and therefore the mechanical performance of the bonding zone 28.
Enfin, il est précisé que la réouverture du couvercle 6 scellé sur le corps principal creux 2 du conteneur 1 peut facilement s'effectuer par fusion des moyens de scellement 26. Cette fusion s'effectue préférentiellement à l'aide d'un chauffage au chalumeau, au laser, par induction ou encore par résistors . Bien entendu, diverses modifications peuvent être apportées par l'homme du métier au conteneur 1 pour matières radioactives et au procédé de fermeture d'un tel conteneur qui viennent d'être décrits, uniquement à titre d'exemples non limitatifs. Finally, it is specified that the reopening of the cover 6 sealed on the hollow main body 2 of the container 1 can easily be carried out by fusion of the sealing means 26. This fusion is preferably carried out using a torch heating. , laser, induction or resistors. Of course, various modifications can be made by a person skilled in the art to the container 1 for radioactive materials and to the method for closing such a container which have just been described, only by way of nonlimiting examples.

Claims

REVENDICATIONS
1. Conteneur (1) pour matières radioactives comprenant un corps principal creux (2) ainsi qu'un couvercle (6) réalisés dans au moins un premier matériau métallique, ledit couvercle (6) étant susceptible d'être fixé sur le corps principal creux (2) par l'intermédiaire de moyens de scellement (26) réalisés dans un second matériau métallique coulé dans une rainure (24) définie par le couvercle (6) et le corps principal creux (2) du conteneur (1), caractérisé en ce que le couvercle (6) et le corps principal creux (2) sont solidarisés auxdits moyens de scellement (26) à l'aide d'une zone de liaison (28), formée par réaction chimique entre les premier et second matériaux métalliques.1. Container (1) for radioactive materials comprising a hollow main body (2) and a cover (6) made of at least one first metallic material, said cover (6) being capable of being fixed on the hollow main body (2) by means of sealing means (26) made of a second metallic material cast in a groove (24) defined by the cover (6) and the hollow main body (2) of the container (1), characterized in that the cover (6) and the hollow main body (2) are secured to said sealing means (26) by means of a connection zone (28), formed by chemical reaction between the first and second metallic materials.
2. Conteneur (1) selon la revendication 1, dans lequel chaque premier matériau métallique est un matériau pris parmi le groupe constitué de la fonte et de l'acier. 2. Container (1) according to claim 1, wherein each first metallic material is a material taken from the group consisting of cast iron and steel.
3. Conteneur (1) selon la revendication 1 ou la revendication 2, dans lequel le second matériau métallique coulé est un matériau pris parmi le groupe constitué du zinc et de ses alliages.3. Container (1) according to claim 1 or claim 2, wherein the second cast metallic material is a material selected from the group consisting of zinc and its alloys.
4. Conteneur (1) selon la revendication 2, dans lequel le second matériau métallique coulé est une fonte, la zone de liaison (28) étant composée d'un alliage fer-carbone.4. Container (1) according to claim 2, in which the second cast metallic material is a cast iron, the connection zone (28) being composed of an iron-carbon alloy.
5. Conteneur (1) selon la revendication 2, dans lequel le second matériau métallique coulé est de l'acier, la zone de liaison (28) étant composée d'un alliage fer-carbone. 5. Container (1) according to claim 2, in which the second cast metallic material is steel, the connection zone (28) being composed of an iron-carbon alloy.
6. Conteneur (1) selon la revendication 2, dans lequel le second matériau métallique coulé est un matériau pris parmi le groupe constitué de l'aluminium et de ses alliages, la zone de liaison (28) étant composée d'un alliage fer-aluminium.6. Container (1) according to claim 2, in which the second cast metallic material is a material taken from the group consisting of aluminum and its alloys, the connection zone (28) being composed of an iron- aluminum.
7. Conteneur (1) selon l'une quelconque des revendications précédentes, dans lequel la zone de liaison (28) dispose d'une épaisseur moyenne (29) comprise entre 10 μm et 5 mm. 7. Container (1) according to any one of the preceding claims, in which the connection zone (28) has an average thickness (29) of between 10 μm and 5 mm.
8. Conteneur (1) selon l'une quelconque des revendications précédentes, dans lequel le couvercle (6) comporte une surface latérale extérieure (22) définissant partiellement ladite rainure (24) et comprenant deux portions adjacentes (30,32) inclinées respectivement d'un angle α et d'un angle β par rapport à une direction (34) parallèle à un axe principal longitudinal du conteneur (38) , les angles α et β étant aigus et opposés afin d'obtenir un effet de coin.8. Container (1) according to any one of the preceding claims, in which the cover (6) comprises an external lateral surface (22) partially defining said groove (24) and comprising two adjacent portions (30,32) inclined respectively by 'an angle α and an angle β relative to a direction (34) parallel to a longitudinal main axis of the container (38), the angles α and β being acute and opposite in order to obtain a wedge effect.
9. Procédé de fermeture d'un conteneur (1) pour matières radioactives comprenant un corps principal creux (2) ainsi qu'un couvercle (6) réalisés dans au moins un premier matériau métallique, ledit procédé comportant une étape de mise en place du couvercle (6) sur ledit corps principal creux (2) du conteneur (1) de manière à former une rainure (24) entre ces deux éléments (2,6), suivie d'une étape de réalisation de moyens de scellement (26) assurant la fixation du couvercle (6) sur le corps principal creux (2) du conteneur (1) en coulant un second matériau métallique dans ladite rainure (24) , caractérisé en ce que l'on choisit le second matériau métallique de sorte qu'il soit apte à réagir chimiquement avec chaque premier matériau métallique, de manière à former une zone de liaison (28) entre d'une part les moyens de scellement (26), et d'autre part le couvercle (6) et le corps principal creux (2) du conteneur (1) .9. Method for closing a container (1) for radioactive materials comprising a hollow main body (2) and a cover (6) made of at least one first metallic material, said method comprising a step of placing the cover (6) on said hollow main body (2) of the container (1) so as to form a groove (24) between these two elements (2,6), followed by a step of producing sealing means (26) securing the cover (6) on the hollow main body (2) of the container (1) by pouring a second metallic material into said groove (24), characterized in that the second metallic material is chosen so that it is capable of reacting chemically with each first metallic material, so as to form a connection zone (28) between on the one hand the sealing means (26), and on the other hand the cover (6) and the hollow main body (2) of the container (1).
10. Procédé selon la revendication 9, dans lequel l'étape de mise en place du couvercle (6) est suivie d'une étape de préchauffage du premier matériau constituant la rainure (24) . 10. The method of claim 9, wherein the step of placing the cover (6) is followed by a step of preheating the first material constituting the groove (24).
11. Procédé selon la revendication 10, dans lequel l'étape de préchauffage est précédée d'une étape de préparation des surfaces (20,22) de la rainure (24) .11. The method of claim 10, wherein the preheating step is preceded by a step of preparing the surfaces (20,22) of the groove (24).
12. Procédé selon la revendication 11, dans lequel l'étape de préparation des surfaces (20,22) de la rainure (24) est réalisée à l'aide d'au moins une technique de préparation prise parmi le groupe constitué des techniques mécaniques, chimiques et électrochimiques de préparation de surfaces, et des techniques de dépôt de couche de matériaux métalliques. 12. The method of claim 11, wherein the step of preparing the surfaces (20,22) of the groove (24) is carried out using at least one preparation technique taken from the group consisting of mechanical techniques , chemical and electrochemical surface preparation, and metallic material layer deposition techniques.
13. Procédé selon l'une quelconque des revendications 9 à 12, dans lequel l'étape de réalisation des moyens de scellement (26) est précédée d'une étape de coulée en excès du second matériau métallique dans ladite rainure (24) pendant une période déterminée, de manière à provoquer un chauffage du premier matériau métallique constituant ladite rainure (24) ainsi qu'un lavage des surfaces (20,22) de cette rainure .13. Method according to any one of claims 9 to 12, in which the step of producing the sealing means (26) is preceded by a step of excessively casting the second metallic material into said groove (24) during a determined period, so as to cause heating of the first metallic material constituting said groove (24) and washing of the surfaces (20,22) of this groove.
14. Procédé selon l'une quelconque des revendications 9 à 13, dans lequel l'étape de réalisation des moyens de scellement (26) par coulée du second matériau métallique dans ladite rainure (24) est suivie d'une étape de chauffage de ce second matériau reposant dans ladite rainure (24) , afin de favoriser la réaction chimique entre les premier et second matériaux métalliques. 14. Method according to any one of claims 9 to 13, wherein the step of producing the sealing means (26) by casting the second metallic material in said groove (24) is followed by a step of heating this second material resting in said groove (24), in order to favor the chemical reaction between the first and second metallic materials.
EP03772388A 2002-10-01 2003-09-29 Container for radioactive materials and method for closing same Withdrawn EP1547097A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR0212115A FR2845196B1 (en) 2002-10-01 2002-10-01 CONTAINER FOR RADIOACTIVE MATERIALS AND METHOD OF CLOSING SUCH A CONTAINER
FR0212115 2002-10-01
PCT/FR2003/002852 WO2004032152A1 (en) 2002-10-01 2003-09-29 Container for radioactive materials and method for closing same

Publications (1)

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EP1547097A1 true EP1547097A1 (en) 2005-06-29

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EP03772388A Withdrawn EP1547097A1 (en) 2002-10-01 2003-09-29 Container for radioactive materials and method for closing same

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US (1) US7321128B2 (en)
EP (1) EP1547097A1 (en)
JP (1) JP2006501457A (en)
FR (1) FR2845196B1 (en)
WO (1) WO2004032152A1 (en)

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Publication number Priority date Publication date Assignee Title
RU2468887C1 (en) * 2011-07-26 2012-12-10 Открытое акционерное общество "Чепецкий механический завод" (ОАО ЧМЗ) Safety device
EP2824671B1 (en) * 2013-07-10 2016-02-03 GNS Gesellschaft für Nuklear-Service mbH Transport and/or storage container and method for closing a transport and/or storage container

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BE596008A (en) 1959-11-06 1900-01-01
EP0042882B1 (en) * 1980-06-28 1985-10-02 Deutsche Gesellschaft für Wiederaufarbeitung von Kernbrennstoffen mbH Device for the receipt, the transportation and the ultimate storage of spent reactor fuel elements
FR2521337B1 (en) * 1982-02-10 1987-01-16 Mitsui Mining & Smelting Co WATERPROOF CONTAINER FOR RADIOACTIVE WASTE
DE3405733A1 (en) * 1984-02-17 1985-08-29 Steag Kernenergie Gmbh, 4300 Essen Method for sealing a metallic cask for shipping and/or long-term storage of radioactive materials, and cask closed using the method
DE3405735A1 (en) * 1984-02-17 1985-08-29 Steag Kernenergie Gmbh, 4300 Essen Method for sealing a metallic cask for shipping and/or long-term storage of radioactive materials, and cask closed using the method
US4700863A (en) * 1986-01-09 1987-10-20 The United States Of America As Represented By The United States Department Of Energy Seal welded cast iron nuclear waste container
US5391887A (en) * 1993-02-10 1995-02-21 Trustees Of Princeton University Method and apparatus for the management of hazardous waste material
FR2733966B1 (en) * 1995-05-11 1997-06-13 Commissariat Energie Atomique CAST IRON CONTAINER WITH SEALED LID BY MELTING LEAD AND METHOD FOR SEALING THE LID ON THE CONTAINER
JPH09262658A (en) * 1996-03-28 1997-10-07 Aisin Seiki Co Ltd Method for joining metallic member

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Also Published As

Publication number Publication date
WO2004032152A1 (en) 2004-04-15
US7321128B2 (en) 2008-01-22
FR2845196B1 (en) 2004-12-03
JP2006501457A (en) 2006-01-12
US20060060801A1 (en) 2006-03-23
FR2845196A1 (en) 2004-04-02

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