JPH0954189A - Double pipe structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double pipe structure which is easy in supporting the inner pipe, has a little weld lines, and is easy in work procedure. SOLUTION: In a double piping in which outer pipe 2 is provided with inner pipe 3, a plurality of support rings 1 is used as support member for supporting the inner pipe, and these support rings 1 of the number of support points are inserted outside the inner pipe 3. A wire 5 is fixed to a support angle 4 provided outside the inner pipe 3 via U-bolts 6. After inserting the outer pipe 2, both ends or one end is fixed and by drawing the wire 5 from the other end, the support rings 1 can be fixed at proper positions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double piping structure for piping used in nuclear facilities such as a spent nuclear fuel reprocessing facility, a radioactive waste treatment facility, or a radioactive management facility building.

[0002]

2. Description of the Related Art Various pipes are installed in nuclear facilities such as reprocessing of nuclear fuel, treatment of radioactive waste or radiation control facility building. Among them, the conventional double pipe structure is shown in FIG. As shown in a) and (b), a support lug 12 is welded to the inner pipe 3 and is loosely attached to the inner surface of the outer pipe 2 to support the inner pipe 3.

[0003]

Since radioactive fluid is handled in nuclear facilities, even if the internal fluid should leak from the piping, the double piping structure prevents the radioactive fluid from flowing to the low dose area side. Has been adopted. When passing a pipe containing a relatively high dose of fluid in a low-radioactive area, non-destructive inspection is required for the welded portion in order to prevent leakage due to defective welding.

However, in the conventional structure in which the support lug 12 is welded to the inner pipe 3, the welding line increases and it is necessary to perform a nondestructive inspection of the welded portion. Further, the outer pipe cannot be constructed unless the pre-use inspection of the lug welded portion is completed, which complicates the construction procedure and takes a long construction period. Further, there is a problem that the number of welded portions to be inspected is increased by the amount of welded lugs and the number of inspection steps is increased accordingly. The present invention has been made to solve the above problems, and an object thereof is to provide a double piping structure in which the inner pipe is easily supported, the number of welded portions is small, and the construction procedure is simple.

[0005]

A first aspect of the present invention is a dual pipe structure comprising an inner pipe and an outer pipe used in a piping system of a nuclear power facility, wherein a support member for supporting between the inner pipe and the outer pipe is provided. It is characterized in that a plurality of the support members are provided outside the inner pipe, and these support members are connected by a wire. A second aspect of the invention is characterized in that the support member is formed by fixing a rivet to an elastic ribbon, and the support member is spirally wound around the inner tube.

A third invention is characterized in that the support member is composed of a plurality of spring wires, and the springs are connected by the wires. A fourth invention is characterized in that the spring wire is spirally wound around the inner tube.

A fifth invention is characterized in that the support member is made of a spacer wire, and the spacer wire is spirally wound around the inner tube. A sixth invention is characterized in that the spacer wire is wound around the inner pipe, and the inner pipe and the outer pipe are provided with a vertical or gradient so that the spacer wire does not have a reverse gradient.

A seventh invention is characterized in that the inner pipe and the outer pipe are integrally bent. An eighth invention is characterized in that a support lug is welded to the inside of the outer tube as the support member.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of a double piping structure according to the present invention will be described with reference to FIG. This first embodiment is an example in which a support ring 1 as a support member is provided on the outer surface of an inner tube 3 and is entirely surrounded by an outer tube 2 in FIG. 1 (a). That is, the lower surfaces of both ends of the inner pipe 3 are brought into contact with the support angle 4, the U-bolt 6 is covered from above the inner pipe 3 and inserted into the support angle 4, and the nut is tightened from the lower end of the U-bolt 6 to support the inner pipe 3. Fix to angle 4.

An end of a wire 5 is fixed to the support angle 4, and the wire 5 penetrates each support ring 1 and fixes the support ring 1. That is, the inner tube 3
A required number of support rings 1 are inserted into the support ring 1, and a wire 5 having a predetermined length is passed through the support ring 1. The wires 5 are fixed on both sides or one side, and the wires 5 are pulled from the other side to fix the support ring 1.

In this case, since the length of the wire 5 stretched on each support ring 1 is set to a predetermined length in advance, the support ring 1 is pulled by pulling the wire 5.
Is the required support support spacing. Then, the inner tube 3
Support settings can be easily performed. The support ring 1 may be formed in a cross shape to support four points as shown in FIG. 1B, or may be formed in a three-pronged shape to support three points as shown in FIG. 1C. You can also

According to the present embodiment, the support ring 1 is connected with the wire 5 at a predetermined interval, and after the inner ring 3 is installed, the wire 5 is pulled from both ends or the other end so that the support ring 1 can be positioned at a required position. Since it can be fixed, the inner pipe 3 in the double pipe can be easily supported at an appropriate position.

Further, since it is not necessary to weld the support ring 1 to the inner pipe 3, there is no welded portion in the supporting portion of the inner pipe 3, and there is no need to perform a welding inspection after the inner pipe 3 is constructed, and thus the inner pipe 3 and After constructing the outer tube 2, it is possible to undergo a pre-use inspection.

Next, a second embodiment of the present invention will be described with reference to FIGS. 2 (a) and 2 (b). In FIG. 2A, the inner pipe 3
As shown in FIG. 2B, a rivet 8 is welded or riveted to the ribbon 7 and a fixed support member is spirally wound around the ribbon 7 and then inserted into the outer tube 3. The inner pipe 3 is supported by the outer pipe 2 by the rivets 8 fixed to the ribbon 7.

The height of the rivet 8 is set so that it can be inserted into the outer tube 2 while being wound around the inner tube 3 and that the rivet 8 can support the inner tube 3. Other parts are shown in Fig. 1.
This is similar to the embodiment shown in (a). The rivet has a cylindrical shape as shown in FIG. 2 (b) and a rivet as shown in FIG. 2 (c).
It is possible to adopt a diamond shape as shown in FIG.

Both ends of the ribbon 7 are fixed by wires 5 to a support or the like provided outside the double pipe so that the support position is not displaced. In addition, by widening the width of the ribbon 7 and winding the ribbon 7 around the inner tube 3 without a gap, the support interval of the inner tube 3 by the support rivets 8 can be made constant.

The support rivet 8 shown in FIG. 2 (c) is formed into a rhombus corresponding to the spiral angle of the rivet 8 so that the ribbon 7 wound on the inner tube 3 is formed. The spiral angle can be fixed, and the support support interval of the inner pipe 3 by the rivet 8 can be kept constant.

According to this embodiment, since the ribbon having the support rivet 8 fixed thereto is wound around the inner tube 3, the inner tube 3
It is possible to have a structure with no welded portion, and after the inner pipe 3 and the outer pipe 2 have been constructed, a pre-use inspection can be performed.

Next, a third embodiment of the present invention will be described with reference to FIG. In FIG. 3, a ring-shaped support spring 10 is inserted as a support member between the inner pipe 3 and the outer pipe 2, and the support spring 10 is connected by a wire 5. After that, the outer tube 2 is inserted, both sides or one side of the wire 5 is fixed, and the wire 5 is pulled from the other side to fix the support spring 10 at a predetermined position in the double pipe. Since the connected wires 5 have a predetermined length in advance, the support spring 10 can be easily installed at a required support interval.
Can be fixed. The outer tube 2 is attached to the partition wall 9.

According to this embodiment, the support spring 10
Has sufficient flexibility, so that the inner tube 3 can have a wide diameter. In addition, by fixing both ends or one end of the wire 5 connecting the support spring 10 and pulling the wire 5 from the other end, the support spring 10 is fixed at a predetermined position and the inner pipe 3 is supported by the support spring 10.
It becomes easy to support. Furthermore, the inner pipe 3 and the outer pipe 2
Since it is not necessary to weld the welding line, the welding line can be eliminated and the pre-use inspection of the welded portion can be performed after the outer pipe is constructed, which is advantageous in the construction process.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In FIG. 4, a support spring 10 is spirally wound around the inner pipe 3 as a support member, and then inserted into the outer pipe 2, so that the inner pipe 3 is supported by the support spring 10 and the outer pipe 2 is attached to the partition wall 9. Fix it.

According to this embodiment, the support spring 10
The inner pipe 3 can be supported with respect to the outer pipe 2 by fixing the other end to the partition wall 9 and spirally winding the support spring 10 around the inner pipe 3. Therefore, the construction can be performed only by winding the support spring 10 around the inner pipe 3, so that the application can be easily applied to pipes having various diameters. In addition, since the inner pipe 3 and the outer pipe 2 can have a structure without welding, the outer pipe 2
After the construction, the welded part can be inspected before use, which is advantageous in the construction process.

Next, a fifth embodiment of the present invention will be described with reference to FIG. In FIG. 5A, the spacer wire 11 as a support member is spirally wound around the inner tube 3 and then inserted into the outer tube 2. Both ends of the spacer wire 11 are fixed to the inner tube 3 or the outer tube 2.

Here, in the present embodiment, if the internal fluid should leak from the inner pipe 3, the leak liquid flows through the gap between the inner pipe 3 and the outer pipe 2 caused by the spacer wire 11, and the outer pipe 2
It has a structure that does not leak to the outside. The number of space wires 11 in this case is the pipe diameter, the inner pipe 3 and the outer pipe 2.
In the illustrated embodiment, a single structure is adopted so that the optimization can be performed by the difference in the caliber. The spacer wire 11 is made of a single wire or a stranded wire made of stainless steel, and the end portion can be fixed to the support outside the double pipe or the end portion of the double pipe outer pipe.

According to this embodiment, only the wire 11 is supported between the inner pipe 3 and the outer pipe 2, and the difference in diameter between the inner pipe 3 and the outer pipe 2 can be reduced. It is possible to make the diameter relatively small, which is advantageous for double piping.
In addition, an inexpensive structure can be obtained. In addition, since the inner pipe 3 and the outer pipe 2 can have a structure without welding, the welded portion can be inspected before use after the outer pipe is constructed, which is advantageous in the construction process.

Next, a sixth embodiment of the present invention will be described with reference to FIGS. 5 and 6A to 6C. This sixth embodiment shows another example of the fifth embodiment and is shown in FIG.
The same reference numerals are given to the same parts as. In FIG. 6 (a), when the inner pipe 3 can be used in a state of full water, it can be used in horizontal pipes as well, but when it is used in a state where there is a free liquid level in the inner pipe 3, a space wire is used. Since a liquid pool 15 is formed between the inner pipe 11, the inner pipe 3, and the outer pipe 2, there is a possibility that the discovery of the leakage may be delayed and may cause a problem.

Therefore, in this embodiment, as shown in FIG.
And whether the outer tube 2 is a vertical part with respect to the partition wall 9,
Alternatively, as shown in FIG. 6 (b) or FIG. 6 (c), the inner pipe 3 and the outer pipe 2 are inclined with respect to the partition wall 9 in a stepwise manner to form a liquid pool between the spacer wire 11 and the pipe. There is no structure. Reference numeral 15 in 6 (a) in the figure
Indicates stagnant leaked liquid, 16 indicates a damaged portion of the inner pipe, and 17 indicates a liquid level of the inner pipe.

In nuclear facilities such as nuclear fuel reprocessing facilities, there are many pipes for transferring fluid by gravity flow. When leakage occurs in the inner pipe 3 in FIG. 6 (a),
When there is a free liquid level inside the inner pipe 3, the leaked liquid is sandwiched between the inner and outer pipes and the spacer wire 11 and is not discharged, so that the discovery of the leak will be delayed.

In the present embodiment, in order to prevent these, a vertical pipe portion is provided, or the pipe is provided with a slope or a slope to prevent the leakage liquid from staying. Therefore, according to the present embodiment, since there is no portion that becomes a liquid pool in the spacer portion between the wire 11 and the inner pipe 3 and the outer pipe 2, when the inner pipe 3 has a free liquid surface, Even if a leak occurs, the leak liquid flows outside the range of the double pipe, and the leak can be found early.

Next, a seventh embodiment of the present invention will be described with reference to FIGS. 7 and 8A and 8B. In this embodiment, when the outer tube 2 has a curved portion, the inner tube 3 and the outer tube 2 are integrally bent. That is, in FIG. 7, the inner pipe 3 is inserted into the outer pipe 2, and the bending spacer 13 is arranged at the bending tool setting position 14 where the bending machine of the inner pipe 3 and the outer pipe 2 are in contact with each other. When this spacer 13 is bent, the inner pipe 3 and the outer pipe 2
Prevents close contact with.

The shape of the bending spacer 13 is shown in FIG. 8 (a).
And (b). After bending, the spacer 13 is removed. Before bending, insert spacer wire 11 into inner tube 3 in advance.
The wire may be spirally wound around and may be bent with a gap between the bending spacers 13 being passed through, or the spacer wire 11 may be inserted after the bending is completed. FIG. 8A shows an example in which the spacer 13 is divided into three and three tongue pieces 13a are provided.
FIG. 8B shows an example in which the spacer 13 is divided into two and has two tongue pieces.

According to this embodiment, the bending spacer 13
Thereby, the inner tube 3 and the outer tube 2 can be bent at the same time. Since this spacer 13 is harder than the pipe, it can withstand a load during bending. Further, since the bending process can be performed at a time with the inner tube 3 and the outer tube 2, and in some cases, the spacer wire 11 inserted, the bending process cost can be reduced by half.

Next, an eighth embodiment of the present invention will be described with reference to FIGS. 9 (a) and 9 (b). In this embodiment, a support lug 12 is welded to the inside of the outer tube 2 as a support material.
As shown in FIGS. 9 (a) and 9 (b), the support lug 12 is welded from the inside to the inside of the outer pipe 2 so that the inner pipe 3 has no welded portion.

With the above structure, however, the welded portion can be concentrated on the outer pipe where welding inspection is not required, the welding inspection can be simplified, and the support lug 12
Is welded in the vicinity of the end of the outer pipe 2, so that it can be easily welded from the inside of the outer pipe 2. Further, since the outer pipe 2 comes into contact with the fluid only when the internal fluid leaks, a welding inspection is required. Absent.

According to this embodiment, since the support lug 12 is welded from the inside of the outer pipe, the welded portion can be concentrated on the outer pipe without requiring nondestructive inspection of the welded portion, and the welded portion can be concentrated on the inner pipe. Since there is no welded part, it can be inspected before use after the outer pipe is installed.

[0036]

According to the present invention, since the inner pipe is structured to be supported by the support ring, the support spring, the support rivet and the wire, there is no welded portion in the inner pipe,
Since the pre-use inspection can be performed after the outer pipe is constructed, the construction procedure can be simplified, and a predetermined inner pipe support interval can be easily set, so that the construction can be shortened.

[Brief description of drawings]

FIG. 1A is a perspective view showing a first embodiment of a double pipe structure according to the present invention with a part thereof cut away, and FIG. 1B is a first example of a support ring used in FIG. 1A. A plan view showing (c)
FIG. 6B is also a plan view showing a second example of the support ring.

FIG. 2 (a) is a perspective view showing a second embodiment of a double pipe structure according to the present invention with a part thereof cut away, and FIG. 2 (b) shows a first example of a ribbon and a rivet in (a). The top view, (c) is a top view which similarly shows the 2nd example of a ribbon and a rivet.

FIG. 3 is a side view showing a third embodiment of the double pipe structure according to the present invention with a part thereof cut away.

FIG. 4 is a side view showing a fourth embodiment of the double pipe structure according to the present invention with a part cut away.

FIG. 5 is a partially cutaway side view for explaining fifth and sixth embodiments of the double piping structure according to the present invention.

FIG. 6 (a) is a side view showing a partially cutaway view for explaining a problem underlying the sixth embodiment of the double piping structure according to the present invention, and FIG. 6 (b) is this embodiment. The side view which shows the 2nd example of this one part notched, and (c) is the side view which shows the third example of this example partially cut away.

FIG. 7 is a side view showing a seventh embodiment of the double pipe structure according to the present invention with a part cut away.

8A is a perspective view showing a first example of a bending spacer in FIG. 7, and FIG. 8B is a perspective view showing a second example of the same.

FIG. 9 (a) is a side view showing an eighth embodiment of a double piping structure according to the present invention with a part thereof cut away, and FIG. 9 (b) is a perspective view showing the main part of FIG. 9 (a).

FIG. 10A is a side view showing a conventional double piping structure with a part cut away, and FIG. 10B is a vertical sectional view of FIG. 10A.

[Explanation of symbols]

1 ... Support ring, 2 ... Outer tube, 3 ... Inner tube, 4 ... Support angle, 5 ... Wire, 6 ... U bolt, 7 ... Ribbon,
8 ... Support rivet, 9 ... Partition wall, 10 ... Support spring, 11 ... Spacer wire, 12 ... Support lug,
13 ... Bending spacer, 14 ... Bending tool setting position, 15 ... Leakage fluid that has accumulated, 16 ... Inner pipe breakage point, 17 ... Inner pipe liquid level.

Claims (8)

[Claims] 1. In a double piping structure comprising an inner pipe and an outer pipe used in a piping system of a nuclear facility, a plurality of support members supporting the space between the inner pipe and the outer pipe are provided outside the inner pipe. A double piping structure characterized by connecting these support members with a wire. 2. The double piping structure according to claim 1, wherein the support member is formed by fixing a rivet to an elastic ribbon, and the support member is spirally wound around the inner pipe. 3. The double piping structure, wherein the support member comprises a plurality of spring wires, and the springs are connected by wires. 4. The double piping structure according to claim 1, wherein the spring wire is spirally wound around the inner pipe. 5. The double piping structure according to claim 1, wherein the support member is made of a spacer wire, and the spacer wire is spirally wound around the inner pipe. 6. The spacer according to claim 1, wherein the spacer wire is wound around the inner pipe, and the inner pipe and the outer pipe are vertically or inclined so that the spacer wire does not have a reverse inclination. Double piping structure. 7. The double pipe structure according to claim 1, wherein the inner pipe and the outer pipe are integrally bent. 8. The double piping structure according to claim 1, wherein a support lug is welded to the inside of the outer pipe as the support member.