JPH01199068A - Pressure vessel - Google Patents

Abstract

PURPOSE:To simplify operations of removing and mounting bolts for a pressure vessel by arranging clamps at least divided into two pieces in the radial direction at the tip of a stud bolt to be implanted in a body flange, wherein the clamps are movable in the radial direction of the stud bolt. CONSTITUTION:The lower engagement part of a stud bolt 1 is constructed with clamps divided into circumferential direction, and the clamp 1b is moved horizontally by inserting a rod 8 into a center hole 9 of the bolt 1 so as to spread to the bolt hole side of a body flange 5, and at this time, the condition shall be such that a parallel groove 5b provided in the body flange 5 and another parallel groove 1f provided in the clamp 1b are put in the state to mesh with each other. Thereby the bolt 1 shall be connected with the body flange 5 through the clamp 1b. Accordingly by drawing off the inserting the rod 8, the stud bolt 1 can be fitted and removed only through horizontal movement of the clamp 1b, wherein the stud bolt 1 is not required to be rotated in a plurality of turns.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure vessel, and more particularly to a stud bolt for fastening the body and lid of a pressure vessel.

[Conventional technology]

The body and upper mirror of a conventional reactor pressure vessel are fastened together with stud bolts. Figure 25 is a cross-sectional view of the reactor pressure vessel, and Figure 26 is an enlarged view of the main parts of Figure 25. The lower engaging portion of the bolt 1 has a threaded structure.

Therefore, when attaching and removing the stud bolt 1 from the fuselage flange 5, by rotating the stud bolt l, the threads of the stud bolt engaging portion la of the stud bolt 1 and the threads of the fuselage flange 5 can be engaged or This is done by letting go.

Such opening/closing work of the upper mirror 7 is normally performed at the time of annual periodic inspection, and fuel exchange of the reactor pressure vessel is carried out.

For this fuel exchange, as shown in FIGS. 27 and 28, a fuel exchange route 1 is inserted from the fuselage flange 5 during fuel exchange.
The stud bolts 1 in range G located at -F are removed, and the stud bolts l in areas other than range G remain implanted and fuel exchange is performed. In addition, depending on the plant output, 76 to 96 stud bolts l are implanted in the fuselage flange 5, and several dozen stud bolts l are removed from the fuselage flange 5 for inspection "131" during the combined use period. It will be done.

Therefore, the removed stud bolts l account for approximately 30 to 40% of the total number of stud bolts.

To remove the stud bolt l, tighten the nut 2 that engages with the stud bolt l using the stud tension 9 and 11 shown in Fig. 29, remove the nut 2 and washer 3, and use the stud handling tool shown in Fig. 30. 1
At step 2, the stud bolt l is lifted and rotated, and the stud bolt l is removed from the body flange 5.

In addition,.

When attaching the stud bolt 1, the above procedure is reversed.

[Problem to be solved by the invention]

As mentioned above, when attaching and removing the stud bolts 1, since the lower engaging part of the stud bolt l has a threaded structure, it is necessary to rotate each stud bolt 1 one by one to attach and remove it from the fuselage flange 5. be.

Incidentally, the dimensions of the stud bolt 1 of the reactor pressure vessel vary depending on the output of each plant, but for the 800Hw class, it has a length of about 1700a and an M150x6 thread, and for the 1l10OH class, it has a length of about 1900+na and an M155x6 thread.

For this reason, it takes time and effort to install and remove the stud bolt 1.

Furthermore, the installation and removal of stud bolts 1 during periodic inspections of nuclear reactors is performed manually in a radioactive area, and is a critical path during periodic inspections of the entire plant.

An object of the present invention is to provide a pressure vessel that solves the above problems, simplifies the work of removing and attaching bolts to the pressure vessel, shortens working time in a radioactive area, and reduces radiation exposure for workers. It's about doing.

[Means to solve the problem]

The above-mentioned object is achieved by arranging a clamp movable in the radial direction of the stud bolt and divided into at least two parts in the radial direction at the tip of the stud bolt to be implanted in the fuselage flange.

[Effect]

The lower engagement part of the stud bolt has a clamp structure in which it is divided into multiple parts in the circumferential direction, and this clamp is moved horizontally so as to spread to the larger side of the fuselage flange bolt, and at this time, the parallel grooves provided in the fuselage flange and the parallel grooves provided in the clamp are This is a stud bolt in which the stud bolt is connected to the fuselage flange via a clamp when the two are engaged with each other. Therefore, the stud bolt can be attached and removed simply by horizontally moving the clamp without rotating the stud bolt multiple times.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

1 to 5 show a first embodiment of the present invention, FIG. 1 is an assembly diagram of a stud bolt in a reactor pressure vessel, and FIG.
The figure is a detailed view of part B in Fig. 1, showing the state when the stud bolts are engaged, Fig. 3 is a detailed view of part B in Fig. 1, showing the state when the stud bolt l is removed, and Fig. 4 is a detailed view of part B in Fig. 1, showing the state when the stud bolt l is removed. C- in Figure 2
A sectional view taken along line C, and FIG. 5 shows a sectional view taken along line DD in FIG.

In the pressure vessel shown in the first embodiment, the lower engaging portion 1a of the stud bolt l has a clamp structure,
A clamp 1b, which is divided into three parts in the circumferential direction of the stud bolt l between the stud bolt l and the body flange 5 in the lower engaging part 1a and has a protruding part along the inner wall circumferential direction, is the stud bolt lower engaging part. 1a. The stud bolt 1 has a center hole 9 formed in its center into which the rod 8 can be inserted, and in the axial direction of the center hole 9,
Several (four in the figure) guide pins 1c are inserted in the radial direction of the stud bolt l from multiple stages (two stages in the figure).
It has a hole through which it can be inserted.

Furthermore, a hole through which the guide pin lc can be inserted is formed approximately in the center between the protrusions of each stage of the clamp 1b. Therefore, the clamp 1b is connected to the stand bolt 1 via the guide pin lc.

Further, springs 1e are provided on the outer periphery of the upper end of the clamp 1b and the outer periphery of the upper end, respectively, and based on the biasing force of the spring 1e, the clamp lb is engaged (the state in which the diameter of the guide pin IC has expanded due to radial movement). When removing (the guide pin lc is in a state where its diameter has become narrower due to radial movement)
It has a function to automatically return to m). Further, the clamp 1b and the body flange 5 can be engaged with each other by parallel grooves 1f and 5b provided on the outer circumference of the clamp 1b and the inner circumference of the body flange 5, respectively.

Next, the operation of the first embodiment configured as described above will be explained.

When the stud bolt 1 is engaged with the body flange 5, the stud bolt 1 is engaged with the body flange 5 in state B (state where the rod 8 is not inserted into the center hole 9 of the stud bolt l) in FIGS. 3 and 8 (A). 5 is inserted. At this time, the clamp lb is contracted by the spring le toward the center of the stud bolt l, and as shown in FIG.
It is smaller than the inner diameter r of the parallel groove 5b.

Also, each guide pin IC is shown in Figure 3 and Figure 8 (A).
As shown in the figure, it is in a state of protruding into the center hole 9 of the stud bolt 1.

In the state shown in Fig. 3, rod 8 is inserted into center hole 9 of stud bolt 1.
When inserted in the direction of the downward arrow, the guide pin lc protruding into the center hole 9 of the stud bolt 1 is pushed outward in the radial direction of the stud bolt 1, as shown in FIGS. 2 and 8(B). It comes into contact with the tip of the hole formed in the clamp 1b. As a result, the clamp 1b is pushed out in the radial direction (outside) and its diameter increases, and the parallel groove 11 provided on the outer periphery of the clamp 1b is inserted into the body flange 5.
The stud bolt 1 becomes attached to the fuselage flange 5 by engaging with the parallel groove 5b provided on the inner circumference of the stud bolt 1.

In this state, the stud bolt 1 cannot be tightly fixed to the fuselage flange 5 (so-called temporary attachment state), but the tapered portion 1g provided on the clamp lb brings the stud bolt 1 into a close contact state.

The effect of force at this time is shown in FIGS. 6 and 7.

When the stud bolt 1 is tightened while the stud bolt 1 and the fuselage flange 5 are connected, an upward force H is applied to the stud bolt 1 due to the tightening force.

The clamp 1b, which receives this force h at the tapered part 1g, is subjected to a force (■) moving in the horizontal direction (outward) by the tapered part 1g, and this causes the stud bolt l to tightly contact the fuselage flange 5 via the clamp 1b. At the same time, the upper mirror flange 4 and the body flange 5 are connected.

After tightening the stud bolt l, the taper part 1g of the stud bolt 1 and the stud bolt l are tightened by force.
Even if the rod 8 in the center hole 9 of the stud bolt 1 is removed, the stud bolt 1 will not loosen or come off.
When the force Ht moves, the force I (the force of the clamp 1b holding down the body flange 5 by a horizontal force) always acts, so the stud bolt 1 does not come off.

When removing stud bolt 1 from fuselage flange 5,
If the rod 8 is removed from the state shown in FIG. 2 and FIG. 8(B) (the state in which the rod 8 is inserted into the center hole 9 of the stud bolt l), and then the stud bolt 1 is loosened, the state shown in FIG. Clamp l as shown in Figure 8(B).
b automatically contracts toward the center of the stud bolt l due to the force of the spring 1e in Figure 9 (B) ■1, and the stud bolt 1
When removed, the outer diameter becomes r, and the rod 8 can be removed from the fuselage flange 5.Also, this can also be done by loosening the stud bolt l while the rod 8 is inserted, and then removing the rod 8. can.

10 to 12 show the second embodiment of the present invention, and the first embodiment
Figure 11 (A) is a vertical cross-sectional view showing the state of the stud bolt 1 when engaged, No. 101m (B) is a vertical cross-sectional view showing the state when the stud bolt 1 is removed, and Fig. 11 (A) is the vertical cross-sectional view showing the state when the stud bolt 1 is engaged.
Figure (A) is a cross-sectional view taken along the - line, Figure 1 (B) is Figure 10 (
B) is a cross-sectional view taken along line L-L of FIG.

In the second embodiment, the rotatably provided stud bolt 1 has a concave portion in the axial direction having a substantially triangular cross section, and each of its three surfaces is formed in a curved shape corresponding to the inner wall surface of the clamp 1b. has been done. In addition, the stud bolt 1 has a plurality of flange-like protrusions in the radial direction (two in the figure).
These protrusions have shapes corresponding to the recesses provided in the clamp 1b. As in the first embodiment, a spring 1e is provided on the clamp 1b, a parallel groove 1e is provided on the outer periphery of the clamp 1b, and a parallel groove 5b is provided on the inner periphery of the body flange 5.

Next, in the second embodiment, FIG.
When the stud bolt 1 is rotated in the direction shown by the arrow in FIGS. 10(A) and 11(A) from the removed state of the stud bolt l shown in FIG. 1(B), the apex of the substantially triangular cross section of the stud bolt 1 By pressing the inner wall surface of the clamp IB at the portion a, the clamp IB expands in the radial direction, and the parallel groove 10 of the clamp IB and the parallel groove 5B of the body flange 5 mesh with each other.

Next, when the stud bolt 1 further rotates in the direction shown by the arrow in the figure from the state shown in FIGS. 10(A) and 11(A), a portion corresponding to the side of the triangle is The stand bolt 1 comes into contact with the curved inner wall surface of the clamp lb, and the clamp lb moves horizontally toward the stud bolt l and contracts, so that the stand bolt 1 can be removed.

FIG. 12 shows a third embodiment of the present invention, which is a modification of FIG. 11. FIG. 12(A) is a cross-sectional view showing a state in which the stud bolts are engaged, and FIG. 12(B) is a cross-sectional view showing a state in which the stud bolts are removed.

In the third embodiment, the stud bolt 1 has protrusions radially formed at equal intervals in the circumferential direction, and these protrusions gradually bulge in one rotation direction from the bottom side, so that adjacent protrusions It has a connected shape near the middle of the section. In addition, the inner wall surface of the three clamps 1b has a recess corresponding to the locus of rotation of the protrusion formed on the stud bolt 1, and a mounting hole corresponding to the side surface of the large bulge of the stud bolt 1. It has a section.

Next, in the third embodiment, when the stud bolt 1 is engaged, as shown in FIG. As a result, the parallel grooves of the clamp Ib (not shown) and the parallel grooves of the body flange 5 engage with each other. When the stud bolt 1 is rotated from this state in the direction shown by the arrow M in FIG. is housed in the recess of the clamp 1b, and the small bulge portion d of the stud bolt 1 abuts against the protrusion of the stud bolt 1, so that the stud bolt 1 can be removed.

13 to 15 show a fourth embodiment of the present invention, in which FIG. 13 is a perspective view of the main part thereof, FIG. 14(A) is a side view showing the state when the stud bolt 1 is removed, and FIG. Figure 14 (B
) is a plan view of Fig. 14 (A), and Fig. 14 (C) is a plan view of Fig. 14 (A).
15 (A) is a side view showing the state of engagement of the stud bolt 1; FIG. 15 (B) is a plan view of FIG. 15 (A); Figure (C) is shown in Figure 15 (
B) is a sectional view taken along line PP.

A guide lh is fitted around the outer periphery of the cylindrical stud bolt 1. This guide 1h has gripping portions formed at equal intervals on the outer circumferential surface side of an annular guide body, and a tree-shaped guide lh is provided below from the guide body in the vicinity of these gripping portions. The multi-lamp lb is divided into three parts in the circumferential direction, and a groove e corresponding to the shape of the dendritic guide 1h is formed in the adjacent side surface of each clamp lb.

A spring le is attached to the outer circumference of the clamp 1b, and parallel grooves are formed on the outer circumference of the clamp 1b and the inner circumference of the body flange 5, respectively.

Next, in the fourth embodiment, when the guide th is inserted from above into the groove e formed by the pair of clamps lb, as shown in FIG. 15), the parallel grooves formed on the outer periphery of the clamp 1b and the inner circumferential surface of the body flange 5 mesh with each other, and the stud bolt 1 can be connected to the body flange 5.

When removing the stud bolt 1°, when the guide lh is pulled upward, the clamp 1b is returned inward by the biasing force of the spring 1e, and the stud bolt l becomes ready to be removed.

16 to 18 show the fifth embodiment of the present invention, and the first
Figure 6 is a perspective view of the main part, Figure 17 (A) is the stud bolt 1
Figure 17 (B) shows the side view of the state when it is removed.
Figure 7 (A) is a plan view, Figure 17 (C) is Figure 17 (B)
18 is a side view showing the state of engagement of the stud bolt l, and FIG. 18(B) is a sectional view taken along the line Q-Q of FIG.
), Fig. 18(C) is a plan view of Fig. 18(B).
FIG.

In the fifth embodiment, a guide 1j is inserted into the stud bolt l. The guide 1j has an annular guide main body provided with three gripping parts at equal intervals, and a square column-shaped part is provided below the guide main body near these gripping parts.

A guide pin I with a circular cross section extends in both directions from two stages in the longitudinal direction (horizontal direction) of these square columnar parts.
K is provided.

As shown in the figure, both sides of the clamp 1b, which is divided into three parts in the circumferential direction, have portions that are inclined outward in the radial direction toward the upper side of the clamp 1b and tapered in the circumferential direction. Two grooves f are formed corresponding to the installation positions of the guide pins IK. Further, it is similar to the previous embodiment in that it has a spring 1e and that parallel grooves are formed on the outer periphery of the clamp 1b and the inner periphery of the body flange 5.

In the fifth embodiment, when connecting the stud bolt 1 to the fuselage flange 5, when the guide 1j is pushed down (in the direction indicated by S in FIG. 17) from the extracted state, the guide pin IK pushes the tapered part of the clamp 1b. The clamp 1b moves toward the fuselage flange 5 side.

FIG. 19 is an explanatory view showing the mechanism when the stud bolt l is removed and engaged. Here, when moving the clamp 1b, (1) when the horizontal distance Mv of the groove f having a tapered portion is equal to the horizontal movement distance U of the clamp 1b, (2) the vertical distance W of the groove f having a tapered portion; , clamp lb
When the distance moved downward or upward is equal, the clamp l
b can be connected to the fuselage flange 5.

When removing the stud bolt 1, the stud bolt 1 is separated from the body flange 5 by pulling up the guide lj.

As described above, in each state, the parallel groove if provided on the outer periphery of the clamp 1b and the parallel groove 5 provided on the body flange 5.
The stud bolt l and the fuselage flange 5 are connected by engaging the bolts b.

The effects of this mechanism will be explained in comparison with a conventional screw structure based on FIGS. 20 to 24.

In FIG. 20, the arrangement state of the uppermost part of the parallel groove in the conventional screw structure or the present embodiment and the two stages below it are indicated by ▪, ▪, and ▪, respectively, and the effects of each will be explained below.

In the case of a conventional screw structure, as shown in Fig. 22, the pitch l of the screws is equal, so the load H applied to the screw threads is highest at the top ■ of the engaged screw parts and gradually decreases as the threads move downward. It's becoming.

Further, due to the load H, elongation α, α', etc. occur in the threaded portion of the stud bolt 1 side. Therefore, as shown by the solid line in FIG. 21, the stress at the top of the threaded portion is high. Therefore, replacing the stud bolt 1 becomes extremely difficult.

On the other hand, the pitch of the parallel grooves in this example is
As shown in Figure 3, the screw pitch Ill on the fuselage flange 5 side
are the same, and the parallel groove pitch on the stud bolt 1 side is 12z
, 1g'', make the upper part smaller and gradually increase the lower part,
That is! , so as to reflect the dimensions α and α′ in consideration of elongation in the pitch l, wmll−α, 1t′=1+ −α′
shall be.

With such a pitch, when a load is applied to the stud bolt l, the pitches of all the parallel grooves are the same, and as shown by the broken line in FIG. 21, the stress at the top part (2) is relatively low. Therefore, the stud bolt 1 can be replaced extremely easily.

Also, the parallel groove pitch on the stud bolt 1 side is the same,
Even if the pitch of the parallel grooves on the five fuselage flanges is changed like the pitch of the parallel grooves on the stud bolt l side in Fig. 23, when a load is applied to the stud bolt l, the load applied to all the parallel grooves cannot be made uniform. , the load applied to the upper groove can be reduced.

In addition, as shown in Fig. 24, the thickness of the parallel groove (j!i, j
! The above effect can also be achieved by changing 4) (increasing the thickness of the parallel grooves on the upper side and decreasing the thickness toward the bottom).

In addition, in the above-described embodiment, an example was shown in which the clamp was divided into three parts in the circumferential direction, but in the present invention, the clamp may be divided into two or four or more parts.

〔effect〕

As described above, according to the present invention, the work of installing and removing stud bolts is simplified, and the work can be easily performed in a short time. Therefore, it is possible to shorten the work of opening and closing lids such as upper mirrors in a radioactive environment, and the radiation exposure of workers can be reduced. Furthermore, even if a harmful defect occurs in the stud bolt engagement portion, the work can be easily carried out by replacing the clamp.

Even if the stud bolt becomes stuck due to rust in the engagement portion of the stud bolt, it is easier to replace the stud bolt compared to the conventional screw structure.

[Brief explanation of the drawing]

Figure 1 is an assembled diagram of stud bolts in a reactor pressure vessel, Figure 2 is a detailed view of section B in Figure 1 showing the engaged state of the stand bolts, and Figure 3 is a diagram of Figure 1 showing the removed state of the stud bolts. A detailed view of part B, FIG. 4 is a sectional view taken along line C-C in FIG. 2, FIG. 5 is a sectional view taken along line D-D in FIG. 4, and FIG. Figure 7 is a detailed view of the J section in Figure 6, Figures 8 and 9.
The figure is a sectional view showing the clamping operation when the stud bolt is engaged and when the stud bolt is removed. FIG. 10 is a sectional view showing the second embodiment of the present invention. FIG. Figure 11 (B) is a cross-sectional view taken along the line - Figure 10 (
12 is a sectional view showing the third embodiment of the present invention, FIG. 13 is a perspective view showing the fourth embodiment of the present invention, and FIG. 14 (A) is a cross section taken along line L-L of B). 14(B) is a plan view of FIG. 14(A), FIG. 14(C) is a θ-θ line cross-sectional view of FIG. 14(B), Figure 15 (A) shows the 13th state when the stud bolt is engaged.
15(B) is a plan view of FIG. 15(A), FIG. 15(C) is a sectional view taken along line P-P of FIG. 15(CB),
16 is a perspective view showing the fifth embodiment of the present invention, FIG. 17(A) is a side view of FIG. 16 when the stud bolt is removed, and FIG. 17(B) is the same as that of FIG. 17(A). Plan, No. 17
Figure (C) is a sectional view taken along the line Q-C in Figure 17 (B), Figure 18 (A) is a side view of Figure 16 when the stud bolt is engaged,
Figure 18(B) is a plan view of Figure 18(A), and Figure 18(B) is a plan view of Figure 18(A).
C) is a sectional view taken along the line R-R in FIG. 18(B), FIG. 19 is an explanatory diagram of the operation of the clamp mechanism in FIG. 16, FIG. 20 is an explanatory diagram showing the screw structure and arrangement of parallel grooves, Fig. 21 is a diagram of stress distribution in a conventional screw structure and parallel grooves; Fig. 22 is an explanatory diagram showing an example of the pitch of the conventional screw structure; Fig. 23 is an explanatory diagram showing an example of the pitch of the parallel grooves in the present invention; FIG. 24 is an explanatory diagram showing examples of changes in groove thickness of the present invention, FIG. 25 is a sectional view of the reactor pressure vessel, FIG. 26 is an enlarged view of section E in FIG. 25, and FIGS. 27 and 28 are A sectional view and a plan view showing the fuel exchange route, FIG. 29 is an explanatory view showing the state of attachment of the stud tensioner to the stud bolt,
FIG. 30 is an explanatory view showing how the stand bolt handling tool is installed. l... Stud bolt, 1a... Stud bolt lower engagement part, 1b... Clamp,
1c...Guide pin, le...Spring,
If...Clamp parallel groove, Ig...Tapered part, 1h...Guide, lj...Guide, lk...Guide pin, f ...Groove, 2...Nut, 3...Washer, 4
... Upper mirror flange, 5 ... Body flange, 5b ... Body flange parallel groove, 8 ...
...Rod, 9...Center hole. Agent Patent Attorney Masaru Nishimoto - Figure 1 Blind Figure 3 Figure 4 Figure 5 Figure 6 Figure 1o (A) (B) (A) (B) Figure 121 (A) (B) Figure 13 Figure 20 Figure 23 Figure 24 Figure 29

Claims (5)

[Claims] (1) In a device in which the tip of a stud bolt is implanted in the body flange to tighten the body and the lid together, the tip of the stud bolt implanted in the body flange is movable in the radial direction of the stud bolt, and the stud bolt A pressure vessel, characterized in that a clamp is arranged in at least two parts in the circumferential direction of the pressure vessel. (2) When the stud bolt is attached to the fuselage flange via the clamp, contact portions between the stud bolt and the clamp are each formed in a tapered shape that slopes upward toward the inside in the radial direction. A pressure vessel according to claim (1). (3) A hole is provided in the axial center of the stud bolt through which a rod can be freely attached and detached, and a guide pin is provided in which the clamp can be moved in the radial direction based on the attachment and detachment operation of the rod. A pressure vessel according to scope item (1). (4) A pressure vessel according to claim (1), characterized in that a protrusion is provided on the outer periphery of the stud bolt, and the clamp is movable in a radial direction based on rotation of the stud bolt. . (5) A groove is formed in the clamp, and a guide is inserted into the clamp, and when the guide is inserted into the groove, the clamp is movable in the radial direction. The pressure vessel described in (1).