WO2023079249A1

WO2023079249A1 - Method for assembling an assembly for sealing a nuclear facility pool and an assembly for sealing a nuclear facility pool

Info

Publication number: WO2023079249A1
Application number: PCT/FR2022/052081
Authority: WO
Inventors: Etienne Carlu; Philippe Leconte
Original assignee: Fives Nordon
Priority date: 2021-11-05
Filing date: 2022-11-04
Publication date: 2023-05-11
Also published as: FR3129024B1; FR3129024A1

Abstract

An assembly (4) for sealing a nuclear facility pool, comprising: a leak-tight coating (5) comprising frame portions (8) and leak-tight plates (9) attached to the frame portions (8); and a formwork (6) that is intended to come into contact with the leak-tight plates (9), devices (7) for clamping the formwork (6), the clamping devices (7) being capable of holding the formwork (6) against the leak-tight plates (9). In said sealing assembly (4), the clamping devices (7) are capable both of being attached to the leak-tight plates (9) and of holding the formwork (6) in contact with the leak-tight plates (9).

Description

DESCRIPTION

TITLE: Method for assembling a sealing assembly for a nuclear facility pool and a sealing assembly for a nuclear facility pool

Technical field of the invention

The invention relates to the field of nuclear installation pools. More specifically, the invention relates to a method of assembling a sealing assembly for a nuclear installation pool. The invention also relates to a sealing assembly for a nuclear installation pool.

Technical background

Nuclear installation pools are used to manage maintenance operations or to store radioactive elements that produce radiation. For example, the radioactive elements can be waste, specific instrumentation, or even a reactor vessel. The water contained in nuclear installation pools is used to stop radiation and, in particular, to evacuate the heat of radioactive elements.

In a nuclear power plant, there are pools in the reactor building and in the fuel building. These pools serve as a storage and/or handling area for radioactive equipment and fuel during maintenance and refueling operations of nuclear reactors.

The pools are filled with borated water. The borated water is filtered and cooled in a closed circuit to avoid any external contamination. Nuclear installation pools must therefore be sealed for obvious safety reasons. The swimming pools are manufactured in two stages. First, a waterproofing assembly comprising a waterproof coating and a temporary formwork is assembled. Secondly, the sealing assembly is positioned opposite side walls defining the outer contour of said swimming pool, the positioning of the sealing assembly being carried out so as to form an empty space between said side walls of one hand and the sealing assembly on the other hand.

The temporary formwork is put in place to prevent the waterproof coating from deforming in the following stages. Indeed, the next operation consists in pouring a concrete in the empty space. The formwork allows the waterproof coating to resist the pressure exerted by the poured concrete and therefore not to deform. Once this concrete has hardened, the formwork can be removed, the waterproof coating then being fixed to the side walls using the hardened concrete.

The waterproof coating is intended to be in contact with borated water. Although the current method used to install the formwork has proven itself, it can still be improved. A disadvantage of the current method is the way the formwork is put in place. According to the current technique, the formwork is held against the waterproof coating by means of devices for pressing said formwork. These tackles are attached to an anchor which is located behind the waterproof covering, on the side walls or on another element located between the side walls and the waterproof covering. Thus, a hole is made in the waterproof coating to allow the pressing device to pass through said waterproof coating. Once the plating devices are removed, these holes are plugged by placing an insert of waterproof liner in the hole and welding it to the rest of the structure.

The current technique weakens the watertightness of the swimming pool. In practice, to solve this problem, many waterproof coating inserts are necessary and many welds must be made. These welds are particularly difficult to achieve and they require specific controls. In addition, the welds made to plug the holes must be regularly inspected during the life of the pool, which extends over several decades.

Thus the current technique is complex in its implementation and longer in duration, which delays the construction site of swimming pools and involves an increase in costs. Finally, the cost of running the pool increases due to weld inspections.

The invention aims to remedy these drawbacks.

Summary of the invention

For this purpose, a set of sealing of a nuclear installation pool is first proposed, comprising:

- a watertight coating comprising frames and watertight plates fixed to said frames and,

- a formwork intended to come into contact with the waterproof plates,

- devices for pressing the formwork, said pressing devices being capable of holding the formwork on the waterproof plates, sealing assembly in which the pressing devices are suitable for being fixed on the one hand to the waterproof plates and for maintaining the other hand the formwork in contact with said sealed plates. This makes it possible to avoid having to make holes in the waterproof plates of the waterproof coating and then to plug the drilled holes at the end of the construction site and makes it possible to speed up the construction of the swimming pool and therefore reduce the duration of the construction site. In addition, it is no longer necessary to inspect any welds.

Various additional features may be provided singly or in combination:

- the plating devices are attached or pre-assembled on the formwork;

- the plating devices are suitable for being glued to the plates waterproof;

- each tackling device includes:

- a plate suitable for being glued to a waterproof plate,

- a rod inserted inside the plate, and

- A movable holding plate along the rod and adapted to come into contact with the formwork to maintain said formwork in contact with the sealed plate; Or

- each tackling device includes:

- a plate suitable for being glued to a waterproof plate,

- a holding element able to exert a force against the temporary formwork and directed towards the waterproof plate,

- a connecting element extending along a plane substantially normal to the sealed plate and able to connect the plate and the holding element. Secondly, a method for assembling a sealing assembly for a nuclear installation pool as previously described is proposed, the assembly method comprising:

- a step of fixing the waterproof plates to the frames, thus forming a waterproof coating,

- a plating step during which the temporary formwork and the waterproof plates are pressed against each other, thus forming the sealing assembly, this plating step implementing plating devices only glued on the sealed plates, said pressing devices being able to maintain the temporary formwork on the sealed plates.

Various additional features may be provided singly or in combination:

- the waterproof plates are not drilled to install the tackle devices;

- the sealing assembly is arranged inside an inner cavity bordered laterally by side walls, so that an empty space is formed between said side walls and the sealed plates;

- this includes a step of filling the empty space at the means of poured concrete;

- this includes a stripping stage after the filling stage, during which, when the poured concrete has hardened, the plating devices are removed so as to separate the formwork from the waterproof plates.

Brief description of figures

Other characteristics and advantages of the invention will appear during the reading of the detailed description which will follow for the understanding of which reference will be made to the appended drawings in which:

[Fig 1] Figure 1 is a schematic representation of a nuclear installation pool comprising a sealing assembly according to the invention.

[Fig 2] Figure 2 is a schematic representation in detail of part of a nuclear installation pool comprising a sealing assembly according to the invention.

Detailed description of the invention

In the drawings, a nuclear installation pool 1 is shown. The nuclear installation pool 1 includes 2 side walls. The side walls 2 define an interior cavity 3. A sealing assembly 4 is fixed to the side walls 2, in order to make the interior cavity 3 sealed.

Sealing Kit 4 includes:

- a waterproof coating 5,

- a temporary formwork 6,

- Devices 7 plating formwork 6 temporary.

The sealed covering 5 comprises frames 8 and 9 sealed plates. The sealed plates 9 are fixed to the frames 8, for example by welding. The frameworks 8 are in the form of profiles meshing the surface of the sealed plates 9. By profile is meant any profile, regardless of the technique used for its manufacture. The sealing assembly 4 is a structure of imposing dimensions and whose mass amounts to several tens of tons. The frames 8, and possibly the temporary formwork 6, give the sealing assembly 4 its overall shape and make it possible, among other things, to keep it during the handling operations of said structure, in particular when moving it for the bring to its final site or even during the implementation of the assembly method of the sealing assembly, in particular during the pouring of the concrete, pouring which then exerts a thrust force on the waterproof coating 5 . It should also be noted that the frames 8 also have the function of ensuring the anchoring of the waterproof coating 5 in the concrete once the latter has been poured.

It should be noted that temporary formwork 6 includes:

- an inner surface of which at least part is intended to come into contact with at least part of the sealed plates 9, and

- an outer surface opposite the inner surface.

The formwork 6 and the sealed plates 9 are held in contact by direct contact or by indirect contact. We speak of direct contact between the formwork 6 and each sealed plate 9 when there is direct physical contact between these two elements. By comparison, we speak of indirect contact between the formwork 6 and the sealed plate 9 when the formwork 6 is in contact with an intermediate element which is itself in contact with the sealed plate 9. In this case, the intermediate element is therefore inserted between the inner surface of the formwork 6 and a sealed plate 9, this intermediate element then being both physically in contact with the formwork 6 and the sealed plate 9. For example, as an intermediate element, mention may be made of a plastic film, an adhesive polymer coating, a steel plate, or any structure composed of at least one of these elements. The 7 tackle devices include:

- a plate 10 adapted to be glued to the sealed plates 9,

- a holding element capable of exerting a force against the outer surface of the temporary formwork 6 and directed towards the sealed plates 9,

- a connecting element extending along a plane substantially normal to the sealed plate 9 and capable of temporarily connecting the plate 10 and the holding element.

Preferably, the plate 10 comprises a housing configured to accommodate, for example by interlocking or screwing, part of the connecting element so as to create a removable mechanical connection between the plate 10 and the connecting element. For example, the housing of the plate 10 can have a square, rectangular, circular section, or a section of another geometry. At least part of the connecting element then has a shape corresponding to the geometry of the housing of the plate 10.

The holding element is configured to cooperate with the connecting element while having a part capable of being in contact with the outer surface of the formwork 6. Preferably, the holding element and the connecting element are connected to one to the other by interlocking so as to temporarily secure the plate 10 and the connecting element. According to a variant, the plate 10 comprises first removable attachment means and the holding element comprises second removable attachment means, the first and second removable attachment means being configured to cooperate with each other. In this case, the combination of the first and second removable fastening means forms the connecting element as defined above. The first and second attachment means are configured so that the holding element exerts the aforementioned force against the temporary formwork 6.

By way of illustration, the first removable attachment means comprise a hook element fixed to the plate 10 and the second removable attachment means comprise an element to be hooked connected to the holding element. In this case, the element to be crocheted is the connecting element as defined above. The hook element and the element to be hooked are configured to cooperate so as to allow, once connected, the holding element to exert the aforementioned force.

Thus, the holding element is temporarily kept in contact with the outer surface of the formwork 6 which is itself temporarily fixed against the sealed plates 9.

Preferably, the part of the holding element which is configured to be in contact with the formwork is substantially flat and parallel to the outer surface of the formwork 6. The substantially flat and parallel surface is preferably substantially perpendicular to the axis substantially normal to the coating along which the connecting element extends.

According to a particular embodiment, represented in FIG. 2, the plating devices 7 comprise:

- a plate 10 adapted to be fixed on the sealed plates 9,

- a rod 11 inserted inside the plate 10 and secured thereto,

- A holding plate 12.

Advantageously, the rod 1 1 is threaded and screwed into the plate 10. Thus the plate 10 has a threaded hole 13 capable of receiving the rod 1 1. The holding plate 12 is movable along the rod 11.

Advantageously, the holding plate 12 comprises a threaded orifice 14 capable of receiving the rod 11. The holding plate 12 is movable along the rod 11 by rotation clockwise or counterclockwise.

Advantageously, an intermediate piece, not shown in the drawings, can be arranged between the temporary formwork 6 and the holding plate 12 in order to distribute the load evenly on said temporary formwork 6.

According to an alternative embodiment, the rod 1 1 is unthreaded and the hole 13 is unthreaded. Thus, the non-threaded rod 11 is inserted into the plate 10 through the unthreaded hole 13 which is able to accommodate the unthreaded rod 11. Thus, the non-threaded rod 11 is fixed to the plate 10. In particular, once the non-threaded rod 11 has been inserted into the non-threaded hole 13, a removable mechanical connection is formed between the rod 11 and the plate 10. The non-threaded rod 11 is coupled to a known clamping means (not shown in the drawings) to ensure the pressing of the holding plate 12 against the formwork 6.

Preferably, the temporary formwork 6 comprises housings 15 able to accommodate the plates 10. For example, a passage 16 made in the temporary formwork 6 makes it possible to insert the rod 11 or the connecting element through said temporary formwork 6. The rod 11 or the connecting element passes through the temporary formwork 6 through the passage 16. The rod 11 or the connecting element is adapted to be connected to the plate 10, for example by screwing, interlocking or hooking as previously mentioned .

In the following, a method for assembling the sealing assembly 4 on a pool 1 of a nuclear installation will be described.

The assembly method includes a first step of fixing the waterproof plates 9 to the frames 8. This fixing is carried out by welding. At the end of the first fixing step, a waterproof coating 5 is obtained which already has a desired general shape.

The assembly method includes a second plating step during which the temporary formwork 6 and the waterproof plates 9 are assembled. This step consists of pressing the temporary formwork 6 and the sealed plates 9 together and then securing them. For this, the plating devices 7 are used. At the end of this step, the sealing assembly 4 is obtained.

According to one example, the plates 10 are initially inserted into the housings 15 of the formwork 6 temporary.

Then, a rod 11 or a connecting element is inserted into the passage 16 and connected to the plate 10. A contact surface 19 of the plate 10 is covered with glue 20. The temporary formwork 6 is then fixed to the sealed plates 9 by gluing the plates 10 on said sealed plates 9.

According to another example, the plates 10 are, initially, fixed to the sealed plates 9 by gluing the plates 10 on said sealed plates 9. Then, the housings 15 and the passages 16 associated with the locations of the plates 10 are made through the formwork 6 temporary. The temporary formwork 6 is then put in place against the sealed plates 9 opposite the housings 15.

Then, the rod 1 1 or a connecting element is inserted into the passage 16 and connected to the plate 10.

According to yet another example, when the temporary formwork 6 is in several parts, the plates 10 are, initially, fixed to the sealed plates 9 by gluing the plates 10 on said sealed plates 9 and placed between parts of the temporary formwork 6 . Then, the rod 1 1 or a connecting element is connected to the plate 10.

A holding element is then connected to the rod 11 or the connecting element. For example, a holding plate 12 is then screwed along each rod 11 until it comes into contact with the temporary formwork 6, or in contact with at least two parts of the temporary formwork 6. Thus the plating devices 7 maintain the temporary formwork 6 fixed to the sealed plates 9 on the one hand thanks to the plates 10 glued to said sealed plates 9 and on the other hand thanks to the holding plates 12 or to the holding elements which ensure the plating formwork 6 temporary against said plates 9 sealed.

Advantageously, the sealed plates 9 are not drilled to install the devices 7 of plating. Indeed, the plates 10 are only glued on the sealed plates 9. This makes it possible to avoid the plugging of the drilled holes at the end of the construction site and makes it possible to accelerate the construction of the swimming pool 1 and therefore to reduce the duration of the construction site. In addition, it is no longer necessary to inspect welds. Advantageously, the assembly method includes a third step of arranging the sealing assembly 4 inside the interior cavity 3 of the swimming pool 1 . This third step can be performed using two different techniques. A first option consists in positioning the assembly 4 of sealing on site, then in erecting the side walls 2 around said assembly 4 of sealing by forming an empty space 18 between said side walls 2 and the plates 9 sealed. A second option consists in first erecting the side walls 2 defining an interior cavity 3 and then positioning the sealing assembly 4 in the interior cavity 3 so that an empty space 18 is formed between said side walls 2 and the plates 9 waterproof. Note that it is also possible to combine the two options for a single pool.

Whichever option is chosen, the sealing assembly 4 is maneuvered using, for example, cranes. So that the sealing assembly 4, on the one hand, retains its general shape during handling operations, and on the other hand is kept in place, stiffening bars are added around and/or inside of sealing assembly 4 . For example, the stiffening bars can take the form of a temporary load-bearing structure (not shown in the drawings) fixed around the assembly 4, in particular to the formwork 6, using any known temporary fixing means. The temporary supporting structure is preferably a metal structure, for example consisting of beams, but is in no way limited to this example.

The assembly method includes a fourth step of filling the empty space 18 with poured concrete. Advantageously, the assembly method includes a fifth stripping step after the fourth filling step. More specifically, when the concrete poured into the space 18 is hardened, the fifth stripping step is initiated. The holding pads 12 or holding elements are removed from the rods 11 or the connecting elements respectively. The temporary formwork 6 is then separated from the sealed plates 9. The plates 10 can be detached using any appropriate means. Thus the surface of the sealed plates 9 and their metallurgical characteristics are never altered, which improves the safety of swimming pools. In the embodiment described above, the plating devices are attached and then fixed to the sealed plates 9 and to the temporary formwork 6. In other words, the plating devices 7 are initially separate from the temporary formwork 6, the two being assembled by the operators on the construction site. According to an embodiment not shown in the drawings, the plating devices 7 are preassembled on the temporary formwork 6. For example, the plates 10 are fixed to the housings 15. This makes it possible to position the temporary formwork 6 more quickly and easily on the sealed plates 9.

Claims

1 . Sealing assembly (4) for a nuclear installation pool (1), comprising:

- a sealed covering (5) comprising frames (8) and sealed plates (9) fixed to said frames (8) and,

- a formwork (6) intended to come into contact with the sealed plates (9),

- devices (7) for flattening the formwork (6), said flattening devices (7) being capable of holding the formwork (6) on the sealed plates (9), sealing assembly (4) in which the devices ( 7) of plating are adapted to be fixed on the one hand to the plates (9) sealed and to maintain on the other hand the formwork (6) in contact with the said plates (9) sealed.

2. Assembly (4) according to claim 1 wherein the devices (7) for plating are attached or preassembled on the formwork (6).

3. Assembly (4) according to any one of claims 1 or 2 wherein the devices (7) for plating are adapted to be glued to the plates (9) sealed.

4. Assembly (4) according to any one of claims 1 to 3 wherein each pressing device comprises:

- a plate (10) adapted to be glued to a waterproof plate (9),

- a holding element capable of exerting a force against the temporary formwork (6) and directed towards the sealed plate (9),

- a connecting element extending along a plane substantially normal to the plate (9) sealed and able to connect the plate (10) and the holding element.

5. Assembly (4) according to any one of claims 1 to 3 wherein each pressing device comprises:

- a plate (10) adapted to be glued to a waterproof plate (9),

- a rod (1 1 ) inserted inside the plate (10), and

- a wafer (12) movable holding along the rod (1 1) and adapted to come into contact with the formwork (6) to maintain said formwork (6) in contact with the sealed plate (9).

6. Method of assembling an assembly (4) for sealing a nuclear installation pool according to any one of claims 1 to 5, assembly method comprising:

- a step of fixing the waterproof plates (9) to the frames (8) thus forming a waterproof coating (5),

- a plating step during which the temporary formwork (6) and the sealed plates (9) are pressed against each other, thus forming the sealing assembly (4), this plating step involving work of the devices (7) of plating only glued on the plates (9) waterproof, said devices (7) of plating being able to maintain the formwork (6) temporary on the plates (9) waterproof.

7. Method according to claim 6 wherein the plates (9) sealed are not drilled to install the devices (7) plating.

8. Method according to any one of claims 6 or 7 wherein the sealing assembly (4) is arranged inside an interior cavity (3) bordered laterally by side walls (2), so that an empty space (18) is formed between said side walls (2) and the sealed plates (9).

9. Method according to claim 8 in which the latter comprises a step of filling the empty space (18) by means of poured concrete.

10. Method according to claim 9, in which the latter comprises a formwork stripping step subsequent to the filling step, and during which, when the poured concrete has hardened, the plating devices (7) are removed so as to separate the formwork (6) of the plates (9) sealed.