WO2016005253A1 - Shielding container for transporting and/or storing radioactive materials - Google Patents

Abstract

The invention relates to a shielding container (10) for radioactive materials, comprising: a container peripheral wall (12); a container bottom (14); and a container lid (16) that closes off the container interior; wherein at least the container peripheral wall is surrounded by a shield (38). In order to ensure an adequate shielding effect while achieving economical production, the shield (38) according to the invention is a sheet-metal strip wound around the container peripheral wall (12).

Description

 SHIELD FOR TRANSPORT AND / OR STORAGE

OF RADIOACTIVE SUBSTANCES

The invention relates to a shielding container for the transport and / or storage of radioactive materials, in particular of non-heat-generating substances, with Behälterumfangswandung, container bottom and container interior final container lid, wherein at least the Behälterumfangswandung is surrounded by a shield which surrounds the Behälterumfangswandung wound sheet metal strip is and extends between a closing element which projects radially from the peripheral wall in the bottom region, and a flange member which projects radially from the lid-side region of the peripheral wall.

EP 2 693 442 A1 discloses a container system for the final disposal of radioactive non-heat-generating waste. The waste receiving container is made of heavy concrete and is surrounded by a receptacle, which in turn is made of normal concrete. The receptacle is closed by a first lid on which a receptacle occlusive second lid is arranged.

A shield transport and storage container according to DE 41 35 066 C1 has a particular consisting of spheroidal graphite container shell with lid receptacle and bottom wall.

The subject of US 4,663,533 A is a storage and transport container for radioactive materials, which has a peripheral wall which consists of coaxially arranged cylindrical elements of different materials. In a container for radioactive substances according to DE 30 08 992 Al a container casing is wrapped with a metal winding, which has γ- shielding function. The metal winding may consist of wire, cable or metal strip. The width of the metal strip is smaller by a multiple than the height of the container wall.

A variety of container types have been developed for the transport and storage - be it temporary storage or final disposal - of non-heat-generating radioactive materials. These include tanks made of steel materials and sandwich containers.

Containers made of steel materials with wall thicknesses in the range between 120 mm and 300 mm are quite expensive to manufacture. There are known from Kugelgraphitgus s existing container, which must be post-processed mechanically after casting. In addition to the casting technique and the necessary post-processing, the quality assurance of the cast monolithic container body by a required non-destructive testing method is particularly costly.

Alternative manufacturing processes - such as forging - could not establish themselves so far. In case of possible separate forging of container casing and bottom and the then required connection through a weld, the cost of manufacturing and quality assurance of the weld is very high. In the case of possible monolithic forging of the shell body and the bottom of the container body very large forging presses are required and compliance with the required material properties is difficult.

The container in sandwich construction, ie consisting of an inner and outer shell made of steel with an intervening shielding layer, although due to the cost-effective materials are cheaper to produce than the previously described container made of steel. However, the shielding layers, which may consist of lead granules or concrete, have material-specific disadvantages: While the use of lead granules, while the density of steel can be achieved, so that the total wall thickness is equivalent to a steel container. However, there are disadvantages due to the low melting point of lead, so that additional fire protection measures are required because the containers must withstand accident fire over a period of 1 hour and a temperature of 800 ° C.

When using concrete - even heavy concrete - densities are far below the density of steel, so that to achieve the same shielding the wall thickness of a sandwich container must be much larger than the wall thickness of a steel container. Thus, with the same outer dimensions, the usable inner volume drops significantly, ie. h., The ratio of volume of the radioactive content to the total volume of the container is much less favorable than the steel container. By maintaining the wall thickness of a steel container for the sandwich container, however, its shielding effect is lower and thus reduces the capacity for radioactive inventory.

The present invention is based on the object, a shielding container of the type mentioned in such a way that at low cost production, a sufficient shielding effect is ensured, so that the cost advantages of a sandwich container achieved, but their disadvantages avoided, while achieving the benefits of shielding steel tanks become.

To achieve the object, the invention essentially provides that at least the outermost layer of the wound sheet-metal strip is sealed in a liquid-tight manner with respect to the closing element, the flange element and the layer running below the outermost layer.

The feature that the wound sheet metal strip forms the shield does not mean that the container itself or its peripheral wall is not already a Shielding function exercises. Rather, the strength of the peripheral wall can already be chosen so that a shield and thus a shielding container are present.

In order to ensure a structurally simple structure with simultaneous secure fixation of the sheet-metal strip, it is provided that the shield extends between the closing element, which protrudes radially from the peripheral wall, ie transversely or perpendicular to the longitudinal axis of the container, and the flange element, which extends from the peripheral wall Lid-side region of the peripheral wall protrudes radially.

The flange element itself should be receptacle for the container lid.

Regardless of this, the invention provides that the flange is connected to the outer surface of the peripheral wall, as welded.

It is also possible that the bottom wall is connected to the inner surface of the peripheral wall, as welded, and protrudes beyond the end edge thereof.

Preferably, it is provided that the flange element and / or the bottom wall consists of a sheet metal such as steel or is a portion of such.

In order to produce the container casing inexpensively, it is provided that the container wall consists of a tube, in particular longitudinally welded tube, preferably made of sheet steel.

In order to allow easy wrapping of the container wall, without slipping of the sheet metal strip, the invention proposes that on the peripheral wall immediately resting layer of the wound sheet metal strip at least partially connected to the peripheral wall, as welded, is.

In this case, the sheet-metal strip should be wound without tension or substantially without tension around the peripheral wall. In this case, it is provided in particular that the width of the sheet metal strip substantially corresponds to the distance between the facing surfaces in the lid region extending flange element and extending in the bottom region end element, so that the metal strips basically only one above the other and not - as the prior art provides - both are arranged side by side and one above the other. As a result, a trouble wrapping the peripheral wall is possible, while ensuring that the required shielding is ensured.

Therefore, the invention is based on a self-inventive suggestion also by a shielding container for the transport and / or storage of radioactive materials, non-heat-generating substances, with Behälterumfangswandung, container bottom and container interior final container lid, wherein at least the Behälterumfangswandung surrounded by a shield which is a sheet metal strip wound around the container peripheral wall and extends between a terminal member projecting radially from the peripheral wall in the bottom portion and a flange member projecting radially from the lid side portion of the peripheral wall, the width of the sheet metal band being the clearance between them facing surfaces of the flange and the end plate corresponds or substantially corresponds. In this case, essentially corresponds means that between the edges of the sheet metal strip and the facing surface of the flange or the end element may optionally be a gap, which is filled by shielding material receiving elongations or required for welding.

A related container is of course combinable with the other features described.

To ensure that between the layers of moisture can not penetrate, at the same time a flawless setting of the sheet metal strip, fiction, according to provided that at least the outermost layer of the wound around the peripheral wall sheet metal strip liquid-tight against the end element, the Flange element and extending below the outermost layer layer, in particular by welding, is completed. In this case, the outermost layer can be sealed off from the layer covered by this by a longitudinal weld seam, or the outermost layer can be connected to the closure element and / or the flange element by a circumferential weld seam.

If there is the possibility that the radial extent of the shield, ie transversely or senrecht to the longitudinal axis of the container, between the flange and the end element is constant or substantially constant, so provides an emphasis on development that radial extent, ie thickness of the shield above height of the container varies. In this way, there is the possibility that targeted increased shielding can be achieved in the areas in which areas of the inventory with highest radioactivity are located within the container.

In terms of dimensions, the invention provides in particular that wall thickness D _{B of} the sheet metal strip is 5 mm <D _B <10 mm and / or wall thickness D _{R of} the peripheral wall formed from the tube is 20 mm <D _R <40 mm and / or the flange element and / or the end member consists of a portion of a sheet such as steel sheet, a thickness D _{s of} 100 mm <D _s <300 mm, preferably 150 mm to 250 mm.

If in principle there is only the need for the layer immediately adjacent to the peripheral wall to be connected to the former, then it is of course also possible to join individual layers to one another as if to be welded. This can be z. B. done selectively during the Wickeins.

The fiction, contemporary steel container with wound steel shield thus avoids the disadvantages of the previously used or designed steel and sandwich container. The steel container with wound shield consists of an inner container made of a preferably longitudinally welded tube made of sheet steel a wall thickness of z. B. 20 mm to 40 mm, the head side of a solid flange and the bottom side is welded to a solid floor. Flange and bottom should each consist of a steel sheet or a portion of such a, which may have a thickness between 150 mm and 250 mm.

By fiction, contemporary teaching, there is the advantage that the peripheral wall, the bottom and the existing of the wound sheet metal shield from each different, requirement-optimized materials can be produced. The peripheral wall, so in particular the longitudinally welded pipe can be made of a Feinkornbaustahl with proven temperature properties to -40 ° C, the soil - as if. Also the cover and the flange - can be made of a metal sheet or a forged part and the shield of relatively inexpensive Material exist.

The container is closed by a particular screwed lid, which can be sealed against the container body, and against the opening side extending flange, by a double seal system. In the lid closing the container may be provided a test opening for the tightness test of the seals. In addition, there is the possibility that in the lid further openings, for example, to fillings, for draining the interior or for drying are available.

The Behälterumfangswandung forming a container with bottom and flange can be easily manufactured according to the prior art.

Although it is known to produce pressure vessels characterized in that wound on a thin-walled base body - for example made of steel - layers of fiber-reinforced plastic or fiber-reinforced ceramic. For example, reference should be made to WO 2007/128837 AI. However, containers of this kind can not be used for the transport and storage of radioactive substances simply because of the lack of shielding effect. Further details, advantages and features of the invention will not become apparent from the claims, the features to be taken from these-alone and / or in combination-but also from the following description of a preferred embodiment to be taken from the drawing.

Show it:

1 is a schematic diagram of a shield, partially cut,

2 shows a section along the line B-B in Fig. 1,

3 is a plan view of the shielding of FIG. 1,

Fig. 4 is a section along the line A-A in Fig. 1 in an enlarged

 Presentation and

FIG. 5 shows a detail X of FIG. 1.

The figures to be taken from the invention shielding 10 for storage and transport of particular non-heat-generating radioactive substances consists of a peripheral wall 12, a container bottom 14 and a container lid 16 as basic elements. The peripheral wall 12 is in particular a longitudinally-welded tube made of sheet steel with a wall thickness between 20 mm and 40 mm.

On the cover side, a flange 18 is attached to the peripheral wall 12, in particular by welding, which has an L-geometry in section, as a comparison of FIGS. 1 and 5 illustrates.

The flange 18 consists of a perpendicular to the container longitudinal axis 20 extending portion 21 and a perpendicular thereto and parallel to the longitudinal axis 20 extending upper portion 22, the radial extent, ie transversely or perpendicular to Longitudinal axis 20, less than that of the section 22 is. Thus, between the sections 21, 22, a step 24, on which the container lid 16 rests, as Fig. 5 illustrates.

It can also be seen from FIG. 5 that the flange 18 is welded to the outside of the container wall 12 at the upper edge, as the weld seam 26 illustrates.

The container lid 16, which in the exemplary embodiment on the outside extends in an aligned manner to the outer edge of the upper portion 22 of the flange 18, by a plurality of particular hexagon socket screws 28 with the flange 18, d. H. the lower portion 21, connected, as is apparent from Figs. 3 and 6.

Of course, there is also the possibility that the cover 16 is sunk into the flange 18, d. h., The upper portion 22 of the flange 18 could survive over the top of the lid 16, z. B. with a measure of 50 mm. In constructions of this kind, the flange area protruding beyond the container lid 16 would have the function of a shock absorber, i. h, deformations in a case towards the lid edge would only affect the flange area, but not the lid 16 itself.

The container lid 16 is sealed off from the flange 18 welded to the container circumferential wall 12 via a double seal 28, 30. In the space between the double seal 28, 30 which can be formed by recessed in unspecified grooves O-rings, runs a test opening 34 in order to check the tightness can.

As for the double seal, it should be noted that the main seal is the inner seal 30 because it seals against the interior of the container. The seal 30 acts radially between the inner container, ie, the longitudinally welded tube 12 and the cover 16. The outer seal also to be designated as an auxiliary seal 28 becomes Required test purposes, continues to act axially, but is moved inwards, so that more space for the screws 27 remains.

With the inside of the peripheral wall 12 of the container bottom 14 is connected, which is in particular made of a steel sheet of a thickness between 150 mm and 250 mm. The container bottom 14 is welded to the peripheral wall 12, as the welds illustrate.

Furthermore, a radially projecting end plate 36, which has an annular geometry and runs perpendicular or substantially perpendicular to the container longitudinal axis 20, extends from the bottom-side edge region of the peripheral wall 12. The end plate 36 is welded to the peripheral wall 12.

In order to ensure the required shielding effect in the region of the peripheral wall 12, fiction, according to provided that a sheet metal strip 38 is wound around the peripheral wall 12, which may preferably have a thickness between 5 mm and 10 mm.

The sheet metal strip 38 can be pulled off a sheet metal coil, wherein the width of the sheet metal strip 38 should be the clearance between the facing surfaces of the flange 18 and the end plate 36.

As Figs. 1 and 2 illustrate, a plurality of plies are wrapped about the peripheral wall 12 to achieve the desired shielding effect. The layers of the metal strip 38 thus form the peripheral shielding of the container 10 according to the invention. The more layers are wrapped, the greater the shielding effect.

In order to avoid an unambiguous fixation and thus the avoidance of slippage of the sheet-metal strip 38 in particular tensionless wrapping of the peripheral wall 12, it is provided that the first layer, ie the directly on the peripheral wall 12, ie the outer surface, resting position connected to this as is welded. This can be done by a longitudinal weld between the longitudinal end edge of the sheet metal strip 38 and the peripheral wall 12.

Then, according to the shielding to be achieved, a desired number of layers are wound around the container wall 12.

According to the embodiment, the thickness of the layers is selected such that their radial extent corresponds to that of the end plate 36 and the lower portion 20 of the flange 18, so that the outer surface of the outermost layer 40 is substantially flush with the end face of the flange 18 and end face of the End plate 36 runs. The outermost ply 40 should then be connected to the underlying layer 42 by a longitudinal seam 44 by welding.

The outermost layer 40 should also be connected to the end plate 36 and the lower portion 20 of the flange 18 by a circumferential weld 46, 48, so that not only a fixation of the layers relative to the flange 18 and the end plate 36 takes place, but at the same time it is ensured that liquid or moisture can not penetrate between the layers.

In the embodiment, the shield, which is determined by the number of wound layers of the metal strip 38, constant over the entire height, so by changing the width of the metal strip 38, the radial extent, ie the thickness of the shield over the height of the container 10th vary, wherein in the area in which inside the container 10 inventory of particularly high radioactivity is located, a higher shield than in other areas can be reached.

Other features to be emphasized which also characterize the teaching according to the invention are the following.

For the sheet-metal strip 38 come sheets of structural steels with lower material properties than for other components of the container 10 in question. Of the Container body, ie the peripheral wall 12 may consist of a sheet of fine grain steels with specified properties at low temperatures (- 40 ° C). Austenitic materials are possible. For the bottom 14, the flange 18 and the lid 16 are also a sheet or a forging of fine grain steels with specified properties at low temperatures (- 40 ° C), in particular austenitic materials in question.

In general, it should be said that the components that define the interior of the container 10, ie in particular referred to as inner container peripheral wall 12, bottom 14, flange 18 and cover 16 of high quality fine grain structural steel with guaranteed toughness properties at - 40 ° C. For the wound shielding a less valuable and thus cheaper structural steel or forged steel can be used. If the materials listed above are non-stainless steels, it goes without saying that it is also possible to produce the peripheral wall 12 forming the inner container, the base 14, the flange 18 and / or the cover 16 from stainless steel. In contrast, the wound shield should still consist of inexpensive structural steel.

Preferred dimensions of the container 10 are:

 Internal diameter 500 mm to 1200 mm,

 Outer diameter 900 mm to 1500 mm,

 Height 1000 mm to 2000 mm,

 Width of the sheet metal strip 800 mm to 1750 mm.

Claims

Shielding container for the transport and / or storage of radioactive materials 1. shielding container (10) for the transport and / or storage of radioactive materials, in particular non-heat-generating substances, with Behälterumfangswandung (12), container bottom (14) and container interior final container lid (16), wherein at least the Behälterumfangswandung of a shield which is a sheet-metal strip (38) wound around the container peripheral wall (11) and radially extending between a closure member (36) projecting radially from the peripheral wall in the bottom region and a flange member (18) protrudes,  characterized ,  in that at least outermost layer (40) of the wound sheet-metal strip (38) is sealed in a liquid-tight manner with respect to the closure element (36), the flange element (18) and the layer (42) running below the outermost layer. 2. shielding container according to claim 1,  characterized ,  the container wall (12) consists of a tube, in particular a longitudinally welded tube, preferably of sheet steel. 3. shielding container according to claim 1 or 2,  characterized , the position of the wound sheet-metal strip (38) resting directly on the peripheral wall (12) is at least partially connected to the peripheral wall as if welded. 4. shielding container according to at least one of the preceding claims, characterized  the outermost layer (40) is sealed off from the layer (42) covered by the latter by a longitudinal weld seam. 5. shielding container according to at least one of claims 1 to 3,  characterized ,  the outermost layer (40) is connected to the closure element (36) and / or the flange element (18) by a circumferential weld seam. 6. shielding container according to at least one of the preceding claims,  characterized ,  the thickness of the shield between the flange element (18) and the end element (36) is constant or substantially constant. 7. shielding container according to at least one of claims 1 to 7,  characterized ,  the thickness of the shield varies over the height of the container (10). 8. shielding container according to at least one of the preceding claims,  characterized ,  in that the extent of the flange element (18) and / or of the terminating element (36) which faces the shield perpendicular to the longitudinal axis (20) of the container (10) is equal to the thickness of the shield. 9. shielding container according to at least one of the preceding claims,  characterized , that wall thickness D _{B of} the sheet-metal strip (38) is 5 mm <D _B <10 mm and / or wall thickness D _{R of} the peripheral wall (12) formed from the tube is 20 mm <D _R <40 mm and / or the flange element (18) and / or the closing element (36) consists of a section of a sheet, such as steel sheet, of a thickness D _{s of} 100 mm <D _s <300 mm. 10. shielding container according to at least one of the preceding claims, characterized  the sheet-metal strip 38) is wound around the peripheral wall (12) without tension or essentially without tension. 11. shielding container according to at least one of the preceding claims,  characterized ,  the width of the sheet-metal strip (38) corresponds or essentially corresponds to the clear distance between the mutually facing surfaces of the flange (18) and the end plate (36).