JPS5886492A - Method of fixing diaphragm floor seal bellows of reactor container - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for installing a reactor containment vessel diaphragm floor seal bellows.

The reactor containment vessel diaphragm floor seal bellows (hereinafter referred to as seal bellows) is installed between the edges of the upper surface of the diaphragm floor that separates the dry well and the high pressure chamber, and maintains airtightness between the dry well and the diaphragm floor. This structure has been developed by the applicant of the present invention and has already been proposed (Japanese Patent Application No. 7420/1989).
(see issue).

This seal bellows has a diameter of about 28 m, which is very large, and cannot be assembled in a factory, so it must be assembled in a dry well. In this case, there is a risk that the seal bellows, which have been partially assembled at the factory, may be welded together on-site.

In the case of the above-mentioned on-site welding, if the welding assembly method used in the factory is the same, non-destructive testing of the on-site welded parts is partially impossible, the integrity of the seal bellows cannot be confirmed, and the assembly is difficult due to shrinkage of the parts due to on-site welding. It is difficult to work with, and has the disadvantage that it is assembled into a seal bellows that cannot perform its original function. Furthermore, since the diameter of the seal bellows is large, welding each ring and each bellows individually in the dry well requires many welding points and is not easy to handle, resulting in a disadvantage that the installation requires a large number of man-hours.

The present invention is intended to eliminate the above-mentioned drawbacks, and its purpose is to enable non-destructive testing of all on-site welds, to improve the integrity of the seal bellows, and to prevent welding during the welding process. To provide a method for installing seal bellows that allows for easy welding and assembly work even when shrinkage occurs, does not impair the function of the seal bellows at all, and reduces the number of man-hours required for on-site installation. It is in.

The feature of the present invention is that on the diaphragm floor, each welding piece is divided into a plurality of pieces in the circumferential direction and brought in and assembled into a ring-shaped welding can, and this is welded on the diaphragm floor; At the top, the lower bellows pieces, which were carried in in plural pieces in the circumferential direction, are arranged in a ring shape, the lower ring pieces are welded together to assemble the lower ring, and this is pulled onto the welding table. Take it out and weld it; attach it above the position, with an intermediate ring piece divided into multiple pieces in the circumferential direction, an upper ring piece with the same length as the middle ring piece, and between both ends of these parts. arranging units in a ring shape, each unit comprising an upper bellows piece that is formed to a length that allows a set interval to exist, and is welded to the intermediate ring piece and the upper ring piece with a set interval left at both ends; Weld the intermediate ring pieces and the upper ring pieces of adjacent units together, and insert a wedge between the intermediate ring piece and the upper ring piece above it through each unwelded end of the upper bellows piece of the same unit to create a gap. a back purge jig is installed in the gap, an adjustment bellows is installed in the space formed between the upper bellows pieces of adjacent units, and the upper bellows piece and the adjustment bellows are welded, Next, the back purge jig and wedge are loosened, and the intermediate ring piece, the upper bellows piece, the adjustment bellows, and the welding remaining parts between the upper ring piece are welded to form an assembly, and this is attached to the lower bellows. Pull out the upper part, weld the rose and the intermediate ring of the assembly to the lower part; then pass the seal plate on,
The dry well, the seal plate, and the upper ring of the assembly are welded together.This configuration enables non-destructive testing of all welded parts on-site, making it easy to weld and assemble even if there is welding shrinkage. A construction method has been developed to install the seal bellows, which can be carried out without impairing the original function of the seal bellows, and which can reduce the number of man-hours required for on-site installation.

The present invention will be explained below based on the drawings.

1 to 5 show one embodiment of the present invention, in which a welded piece divided into a plurality of pieces in the circumferential direction is carried above the upper surface of a diaphragm floor 2 made of a steel plate. The equal welded pieces are combined into a ring-shaped welding can 3 above the diaphragm floor 2, and this is welded and fixed to the peripheral edge of the diaphragm floor 2, as shown in FIG.

Next, for installation, the lower bellows pieces that are divided into multiple pieces in the circumferential direction are brought into the upper position, arranged in a square/gang shape, and the lower ring 4 is assembled by welding the adjacent lower bellows pieces together. , the lower ring 4 is pulled out and welded onto the welding table 3 as shown in FIG. Reference numeral 5 in FIG. 1 is the welded portion.

Next, for installation, a unit 6 consisting of an intermediate ring piece 7', an upper bellows piece 8', and an upper bellows piece 9', which are divided into a plurality of pieces in the circumferential direction, is carried above the lower bellows 4. do.

Regarding each part constituting the unit 6, as shown in FIG. 2, the intermediate ring piece 7' and the upper ring piece 9' are formed to have the same length, and the upper bellows piece 8' The length is such that there is a set interval t1 between both ends of / and 9/. The upper bellows piece 8' is welded and integrated with the intermediate ring piece 7' and the upper ring piece 9', respectively, leaving a set interval t2 at both ends. Up to this point, it has been assembled at a factory. There is. In FIGS. 2 and 3, reference numeral 1o indicates a weld between the intermediate ring piece 7' and the upper bellows piece 8', and 11 indicates a weld between the upper bellows piece 8' and the upper ring piece 9'. .

The units 6 carried above the bellows 4 at the site are assembled in a ring shape, and as shown in FIG. /, 97 are welded together and a non-destructive test is performed on the welded portion. In FIG. 3, reference numeral 12 indicates a weld between the middle ring pieces, and reference numeral 13 indicates a weld between the upper ring pieces.

Then, as shown in FIG. 5, a wedge 14 is inserted between the intermediate ring piece 7' and the upper ring piece 9' above it through both unwelded ends of the upper bellows piece 8' of the unit 6.
．． 14, to form a gap 15.15 sufficient for welding the adjusting rose 8" and performing a non-destructive test of the welded part, and in each gap 15.15, a back purge cure used for welding. Fit the tools 16, 16.

and the upper bellows piece 8' of the adjacent unit 6.6,
An adjustment bellows 8" having the shape shown in FIG. 4 is installed in the space formed between the upper bellows pieces 8/, s
/ and the adjustment bellows 8'' were welded, then the back purge oil AI 6, 16 was removed, and a non-destructive test was performed on the welded parts of each of the above members.
Remove numbers 4 and 14. In FIG. 5, reference numeral 17 indicates a welded portion between the upper bellows piece 8' and the adjustment bellows 8''.

By removing the wedges 14, 14, the gap between the intermediate ring piece 7', the upper bellows piece 8', the adjusting bellows 8'' and the upper ring piece 9' is removed.

Next, weld the remaining welds between the intermediate ring piece 7', the upper bellows piece 8', the adjusting bellows 8 and the upper ring piece 9', respectively, and assemble the intermediate ring 7, the upper bellows piece 8', and the adjusting bellows 8''. The upper bellows 8 and the upper ring 9 are connected
constitute an integrated assembly.

Then pull the assembly down onto the lower bellows 4,
As shown in FIG. 1, the mating surfaces of the lower bellows 4 and the intermediate ring 7 of the assembly are welded. Reference numeral 18 in FIG. 1 indicates the welded portion.

After welding the lower bellows 4 and the intermediate ring 7, the seal plate 19 is passed between the upper ring 9 and the dry well 1, and the respective joints are welded to complete the installation of the seal bellows.

Reference numeral 20 in FIG. 1 indicates the upper ring 9 and the seal plate 19.
1 shows a weld between the dry well 1 and the seal plate 19.

The present invention has the configuration described above, and according to the present invention, a non-destructive test can be arbitrarily performed on the on-site welded part, so it has the effect of significantly improving the integrity of the seal bellows, and also has the effect of significantly improving the integrity of the seal bellows. Even if there is welding shrinkage during the process, welding and assembly work can be carried out without any hindrance, and the welding and assembly work can be carried out without impairing the function of the seal bellows, and on-site installation requires less man-hours. There are also benefits that can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a portion of the seal bellows welded and assembled according to the present invention, Fig. 2 is a perspective view of a unit consisting of an intermediate ring piece, an upper bellows piece, and an upper ring piece, and Fig. 3 shows how the units are shown together. lacquer, a perspective view of a portion of the assembled assembly; FIG. 4 is a perspective view of the adjustment bellows fitted into the spaces between the upper bellows pieces of the unit; FIG.
This figure is a view seen from arrow A in FIG. 3, and shows the state of the adjustment bellows shown in FIG. 4 when welding. 1...Dry well, 2...Diaphragm floor,
3... Welding table, 4... Lower heros, 6... Unit, 7'... Intermediate ring piece, 7... Intermediate ring,
8'... Upper bellows piece, 8"... Adjustment bellows, 8... Upper bellows, 9'... Upper ring piece, 9
... Upper ring, 14 ... Wedge, 15 ... Gap, 16 ... Back barge jig, 19 ... Seal plate, 5, 10, 11° Fig. 1 No. 3 (2) Kudzu lr mouth 3rd (2)

Claims (1)

[Claims] 1. (4) On the diaphragm floor, each welding table piece that has been divided into a plurality of pieces in the circumferential direction and brought in is assembled into a ring-shaped welding table, and this is welded on the diaphragm floor. ■ At the upper part of the installation position, each lower bellows piece, which was delivered in multiple pieces in the circumferential direction, is arranged in a ring shape.
Assembling the lower ring by welding the lower ring pieces together,
・Pull this out onto the welding table and weld it; (Q) Attachment is done by attaching an intermediate ring piece divided into a plurality of pieces in the circumferential direction above the position, and an upper part having the same length as the intermediate ring piece. a ring piece; and an upper bellows piece formed to a length that allows a set interval to exist between both ends of these pieces, and welded to the intermediate ring piece and the upper ring piece with a set interval left at both ends. Arrange the units in a ring shape, weld the intermediate ring pieces and the upper ring pieces of adjacent units together, and insert the intermediate ring pieces and their Insert a wedge between the upper ring pieces to form a gap, fit the back purge jig into the gap, and insert the adjustment bellows into the space formed between the upper bellow pieces of adjacent units. Attach the upper bellows piece and the adjustment bellows, weld them together, then pull out the back purge jig and wedge, and weld the intermediate ring piece, the upper bellows piece, the adjustment bellows, and the upper ring piece, respectively. Weld the assembly to form an assembly, pull it down onto the lower bellows, weld the lower bellows and the middle ring of the assembly; The installation method of the reactor containment vessel diaphragm floor seal bellows is characterized by: welding;