JP2004212336A - Clamping device and clamping method for jet pump instrumentation tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a clamping device and a clamping method for a jet pump instrumentation tube, made capable of reducing stresses, even if a fluid oscillation is given to welded parts of a support and an instrumentation tube of diffuser, from all directions. <P>SOLUTION: The body 23 of a C-shape arm 22 having two projections 24 is provided with a pressing member 28 pressed by a first wedge member 27 against a diffuser 14 and a drawing member 33 drawn by a second wedge member 32 in a direction of parting from the diffuser 14 so that the instrumentation tube 20 is clamped firmly in a pinched state by the pressing member 28 and the drawing member 33. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a measuring pipe for measuring a flow rate of a jet pump in a pressure vessel of a boiling water reactor, and more particularly to a measuring pipe clamp device and a clamp attached to a jet pump diffuser via a support. About the method.
[0002]
[Prior art]
A boiling water reactor has a recirculation system in its pressure vessel. A jet pump is used in this recirculation system. Therefore, an example of such a boiling water reactor recirculation system will be described with reference to FIG.
[0003]
Here, in FIG. 8, reference numeral 1 denotes a reactor pressure vessel, in which a plurality of jet pumps 2 are provided so as to surround the reactor core 4, whereby the reactor recirculation system is provided together with the recirculation pump 3. Is formed, and a coolant (reactor water) at a flow rate necessary for changing the output of the nuclear reactor is supplied to the reactor core 4.
[0004]
At this time, a part of the coolant 5 forcibly circulating through the reactor core 4 is taken out of the reactor pressure vessel 1, pressurized by the recirculation pump 3, and then becomes high-speed driving water from the nozzle of the jet pump 2. Is injected. Therefore, the coolant 6 around the nozzle is sucked into the jet pump 2 by this high-speed jet fluid, mixed with the driving water therein, sent to the lower plenum 7 of the core, and recirculated.
[0005]
Next, the structure of the jet pump 2 will be described with reference to FIG. 9. In this figure, 8 is a riser elbow, 9 is a riser pipe, 10 is a transition piece, 11 is an elbow, 12 is a nozzle, 13 is an inlet mixer, and 14 is a diffuser. , 15 is a bracket, 16 is a support, 17 is a wedge, 18 is a beam, 19 is a riser brace, 20 is a measuring tube, and 21 is a measuring tube support.
[0006]
Here, the measuring pipe 20 is provided for transmitting the pressure in the diffuser 14 to a differential pressure gauge provided outside the reactor pressure vessel and measuring the flow rate. At this time, in the prior art, a clamp device is attached to the measuring pipe to restrict the measuring pipe from two directions (for example, see Patent Document 1). ).
[0007]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 9-90085
[Problems to be solved by the invention]
The jet pump is installed in the reactor coolant in the reactor, and the high-speed fluid flows inside the reactor, so that the jet pump is affected by fluid vibration from the external and internal fluids. Then, this vibration is transmitted to the measurement pipe. At this time, if the frequency of this vibration matches the frequency of the natural vibration of the measurement pipe, the load acting on the measurement pipe increases due to resonance, and the measurement pipe itself and the measurement pipe And may damage the weld of the measuring tube support.
[0009]
Here, as a method of repairing the measuring pipe in the event of damage, welding or mechanical joints can be used, but since this repair work is underwater work, the repair equipment is also large, and The repair work will take a long time.
[0010]
Therefore, it is necessary to prevent damage to the measuring tube itself and the welded portion between the measuring tube and the measuring tube support. However, in the above-described conventional technology, it cannot be said that sufficient consideration is given to this point. There remained a problem in securing the security.
[0011]
Here, the above-mentioned prior art is to attach the clamp device to the measuring pipe, but at this time, the measuring pipe is restrained from two directions, and therefore, when the load acting on the measuring pipe increases due to resonance. Problems remain in reliability.
[0012]
The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to reduce stress caused by fluid vibration from all directions to a welded portion of a diffuser support and a measuring pipe even when the fluid vibration is applied from all directions. It is an object of the present invention to provide a clamp apparatus and a clamp method for a jet pump measuring tube.
[0013]
[Means for Solving the Problems]
An object of the present invention is to provide a clamp device for a jet pump measurement pipe, which clamps a measurement pipe for flow measurement attached to a diffuser of a jet pump installed in a reactor pressure vessel via a support, in a jet pump measurement pipe in contact with an outer surface of the diffuser. Arm, a body provided at one end of the arm, a first wedge member movably held on the body via a tightening bolt, and one end engaged with the first wedge member at one end. Is pressed against the outer surface of the measuring tube, a second wedge member movably held on the body via a tightening bolt, and one end is engaged with the second wedge member and the other end is A detent member abutting on the outer surface of the measuring tube, wherein the pressing member is abutted on a surface of the measuring tube having the support opposite to the support, and the detent member is In the portion having the support tube is in contact with the surface of the same side as the support is achieved so as to be clamped in a state where the measuring tube is sandwiched.
[0014]
At this time, the above object can be achieved even if at least one round hole is formed in the C-shaped arm, and the hole is formed on the upper surface of the C-shaped arm and one of the bodies in the same direction as the curvature of the arm. The above-mentioned object can be achieved in the same manner even if at least one hanging metal fitting having an opening is provided, and a portion of the C-shaped arm which is in contact with the diffuser is 90 ° or more with respect to the center of the diffuser. The above object can also be achieved by providing two projections arranged with an opening of a degree or less.
[0015]
Further, at this time, the detent member may be provided with a tip portion abutting on the lower surface of the support, and at this time, the detent member is provided with a hook-shaped hook abutting on the side surface of the support. At this time, the detent member may be provided with members located on the upper surface and the lower surface of the support, and the member on the upper surface of the support may be longer than the member of the support. At this time, a notch may be formed in an intermediate portion of the pressing member in contact with the outer surface of the measurement tube.
[0016]
Similarly, at this time, the length from the lower surface of the support to the lower side of the portion in contact with the measurement tube of the pressing member may be 200 mm or more, and the first wedge member and the second wedge member may have: A pin for preventing the fastening bolt from coming off may be provided adjacent to the fastening bolt.
[0017]
On the other hand, the object is to provide a method for clamping a jet pump measurement pipe using any one of the above-described clamp devices for a jet pump measurement pipe, wherein the first wedge member and the second wedge member are the first one. The above object can be achieved even if the pressing member is pressed against the measuring tube by the wedge member, and then the retaining member is drawn to the measuring tube by the second wedge member.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a clamp device for a jet pump measurement pipe according to the present invention will be described in detail with reference to the illustrated embodiments. Here, FIG. 1 is a top view of one embodiment of the present invention, FIG. 2 is a side view, FIG. 3 is an enlarged top view of a part a of FIG. 1, and FIG. 4 is a top view of only the body of FIG. 5 and FIG. 6 are side views in which a portion b of FIG. 2 is enlarged and a part is further sectioned, and FIG. 7 is a three-dimensional view of a retaining member.
[0019]
Here, first, in FIGS. 1 to 7, the clamp device according to this embodiment is represented by 57. The clamp device 57 includes a C-shaped arm 22, and the body 23 is provided at one end of the arm 22. The diffuser 14, the measuring tube 20, and the measuring tube support 21 are as described in the related art.
[0020]
As shown in FIG. 1, the arm 22 has two protruding portions inward at two points, that is, a front end portion and a halfway opening from the center of the diffuser 14 with respect to the front end portion. When the projections 24 come into contact with the outer surface of the diffuser 14, the arm 22 comes into contact with the diffuser 14 at almost two points and is properly held.
[0021]
If the angle formed by the two projections 24 at this time is large, the bending stress acting on the arm 22 becomes too strong when the arm 22 is supported at three points on the diffuser 14, which will be described later. In practice, it is desirable to set the angle between 90 degrees and 100 degrees.
[0022]
Further, on the upper surfaces of the arm 22 and the body 23, a suspending member 25 is provided. The suspending member 25 has the same curvature as that of the arm 22, particularly as clearly shown in FIG. There is provided a hole 25a through which the hanging rope is opened toward the direction, and the rope passed through the hole 25a of the hanging bracket 25 interferes with the diffuser 14 when the clamp device 57 is attached to the diffuser 14. It is made to be able to prevent.
[0023]
Further, a round hole 26 is provided at the tip of the arm 22. Here, the round hole 26 is used as a substitute for a suspending fitting when the clamp device 57 is attached, and is used for finely adjusting the position of the tip of the arm 22.
[0024]
Next, as shown particularly in FIG. 4, the body 23 has a groove 29 into which the first wedge member 27 and the pressing member 28 are inserted, a screw hole 31 into which the tightening bolt 30 is screwed, and a second hole. A groove 34 into which the wedge member 32 and the retaining member 33 are inserted and a screw hole 36 into which the tightening bolt 35 is screwed are provided.
[0025]
At this time, as shown in FIG. 5, a notch 28A is formed in an intermediate portion of the portion where the pressing member 28 is in contact with the measurement tube 20, so that the measurement tube 20 is bent. Also, the upper and lower portions of the pressing member 28 in contact with the measuring tube 20 can be brought into contact with each other.
[0026]
At this time, as shown in FIG. 5, the length from the lower surface of the support 21 to the lower side of the portion of the pressing member 28 in contact with the measurement tube 20 is set to 200 mm or more. Can be further reduced.
[0027]
Here, as shown in FIG. 5, the first wedge member 27 is provided with a hole 37 into which the fastening bolt 30 is inserted, and a hole 39 for inserting a pin 38 is provided above the hole 37. Are provided at right angles to each other. The pin 38 connects the first wedge member 27 and the tightening bolt 30 so that when the tightening bolt 30 is rotated, the tightening bolt 30 and the first wedge member 27 simultaneously move up and down. I do.
[0028]
A washer 40 for preventing loosening after tightening is provided integrally with the tightening bolt 30 at an upper portion of the tightening bolt 30. Although not shown, a washer is provided by using a dedicated device. 40 is bent to prevent loosening after tightening.
[0029]
Although not shown, a groove in the shape of a kana character is provided at the tip of the first wedge member 27, and a protrusion in the shape of a kana character provided in the pressing member 28 is provided. (Not shown), whereby when the tightening bolt 30 is rotated, the wedge portion 41 of the first wedge member 27 moves up and down and engages with the first wedge member 27. The combined pressing member 28 is moved left and right as indicated by an arrow 42.
[0030]
A U-shaped groove 43 is provided at the tip of the pressing member 28 as shown in FIG. 3, and the measuring tube 20 is engaged with the groove 43.
[0031]
On the other hand, as shown in FIG. 6, the second wedge member 32 is provided with a hole 44 into which the tightening bolt 35 is inserted. Above the hole 44, the hole 46 for inserting the pin 45 is provided. It is provided orthogonal to the hole 44 formed.
[0032]
The pin 45 connects the second wedge member 32 and the tightening bolt 35. Therefore, when the tightening bolt 35 is rotated, the tightening bolt 35 and the second wedge member 32 move up and down simultaneously.
[0033]
At this time, a washer 47 for preventing loosening after tightening is provided integrally with the tightening bolt 35 above the tightening bolt 35. Then, although not shown, the washer 47 is bent using a dedicated device so that loosening after tightening can be prevented.
[0034]
Although not shown, a groove shaped like a kana character is provided at the tip of the second wedge member 32, and this groove has a shape similar to a kana character provided on the retaining member 33. When the fastening bolt 35 is rotated by this, the wedge portion 48 of the second wedge member 32 moves up and down, so that the second wedge member 32 The detent member 33 fitted with is adapted to be moved right and left as indicated by an arrow 49.
[0035]
As shown in FIG. 7, the detent member 33 has an L-shape as a whole, and the L-shaped tip is vertically divided to form tip portions 50 and 51. The distal end portions 50 and 51 are configured to be in contact with the measuring tube 20. Here, the distal end portion 50 is further longer than the distal end portion 51.
[0036]
As a result, the lower end portion 51 is in contact with the lower surface of the support 21, thereby suppressing the whole of the clamp device 57 from floating due to the taper of the diffuser 14. A hook-shaped hook 62 is provided at the tip of the letter-shaped distal end 51 so as to face upward, so that movement of the clamp device 57 in the rotation direction can be prevented.
[0037]
Next, a procedure for attaching the clamp device 57 according to this embodiment to the measurement pipe of the jet pump in the reactor pressure vessel will be described with reference to FIGS. 10 and 11. In this case, after the reactor is stopped, FIG. As shown, the lid of the reactor containment vessel and the lid of the reactor pressure vessel 1 are first removed. Thereafter, the reactor well 52 is filled with water 53, and then the steam dryer and the steam separator in the reactor pressure vessel 1 are removed.
[0038]
Then, in this state, the work of attaching the clamp device 57 to the measuring pipe is performed. At this time, first, as shown in FIG. 10, on the refueling cart 54 or on the working cart (not shown). After passing the rope 55 through the hanging bracket 25 of the clamp device 57, the tip of the rope 55 is tied to the handrail 56 on the carriage 54 and fixed. At this time, if the clamp device 57 is difficult to move, the rope 55 may be passed through the hole 26 of the arm 22.
[0039]
Next, the clamp device 57 is gradually lowered from the carriage 54 while loosening the rope 55, and the clamp device 57 is temporarily installed at a predetermined position of the diffuser 14 by operating a plurality of ropes 55 as shown in FIG. I do.
[0040]
At this time, the method of installing the device at a predetermined position is to first put the distal end portion 50 of the retaining member 33 temporarily on the support 21 and then rotate the clamp device 57. At this time, since the distal end portion 50 is longer than the distal end portion 51, temporary setting can be easily performed.
[0041]
Next, the plurality of ropes 55 are pulled upward, the whole clamp device 57 is slightly moved upward, and the member 51 of the retaining member 33 is brought into contact with the lower surface of the support 21.
[0042]
Next, in this state, although not shown, an operating pole having a hexagon socket wrench at the tip is used, and a hexagon socket at the tip is inserted into a hexagon head 58 (FIG. 5) at the head of the tightening bolt 30. When the tightening bolt 30 is rotated clockwise to rotate the first wedge member 27 downward, the pressing member 28 moves in the direction of the diffuser 14 and the U-shaped groove 43 at the tip end of the retaining member 28. Is in close contact with the measuring tube 20, so that the diffuser 14, the measuring tube 20, and the clamp device 57 are integrally fixed.
[0043]
Next, although not shown, the hex socket at the tip of the operating pole is inserted into the hex head 59 (FIG. 6) of the head of the tightening bolt 35, and the clockwise rotation of the tightening bolt 35 is performed. By doing so, the second wedge member 32 descends, and the retaining member 33 moves in the direction of the measuring tube 20, whereby the L-shaped tips 50 and 51 of the retaining member 33 are further attached to the measuring tube 20. Strongly adheres.
[0044]
Thereafter, a washer folding device (not shown) is lowered from the carriage 54, and the washers 40 and 47 provided integrally with the tightening bolts 30 and 35 are bent, and the folded states 60 and 61 are shown in FIG. That is, the tightening bolts 30 and 35 are prevented from loosening.
[0045]
Then, in the case of this embodiment, the pressing member 28 and the retaining member 33 sandwich the measuring tube 20 from both sides, and the measuring tube 20 is tightened with a strong force by the wedge action of the first wedge member 27 and the second wedge member 32. Therefore, the holding of the counter tube 20 by the clamp device 57 is provided very strongly.
[0046]
At this time, the clamp device 57 itself has two protrusions 24 provided on the C-shaped arm 22 abutted on one side of the diffuser 14 at an angle of, for example, 100 degrees. On the body 23 side, the pressing member 28 is pressed with a strong force against the diffuser 14 via the measuring tube 20 and the support 21 by the wedge action of the first wedge member 27. Will be held firmly.
[0047]
Therefore, according to this embodiment, regardless of the direction of the stress due to the fluid vibration of the diffuser 14, the stress applied to the measuring pipe 20 can be reliably reduced, and as a result, the safety of the plant can be improved and the stable operation can be ensured. it can.
[0048]
Here, the effects of the above embodiment will be listed as follows.
[0049]
According to the above-described embodiment, the stress appearing in the measurement pipe of the jet pump due to the fluid vibration can be reduced, and the effect of preventing the measurement pipe from being damaged can be obtained.
[0050]
Further, according to the embodiment in which the C-shaped arm 22 is provided with the round hole 26, the position of the tip of the arm can be finely adjusted through the rope through the round hole at the time of mounting the clamp device. Can be easily installed.
[0051]
Next, according to the embodiment in which the hanging fitting 25 is provided on the C-shaped arm 22, when the clamp device is attached through the rope, the rope can be operated without interfering with the diffuser.
[0052]
Next, according to the embodiment in which the C-shaped arm 22 is provided with the two protrusions 24 at an opening angle of 100 degrees or less and 90 degrees or more, the two protrusions are brought into accurate contact with the outer surface of the diffuser. be able to.
[0053]
Next, according to the embodiment in which the retaining member 33 is provided with the distal end portions 50 and 51, there is no possibility that the clamp device will rise from the initially set position during the operation of the plant, so that the set position is securely maintained. be able to.
[0054]
Next, according to the embodiment in which the retaining member 33 has the hook-shaped hook 62, there is no possibility that the clamp device rotates during plant operation, so that the set position can be reliably maintained.
[0055]
Next, according to the embodiment in which the retaining member 33 is provided with the distal end portions 50 and 51 and the distal end portion 50 is longer than the distal end portion 51, the temporary setting of the clamp device can be easily performed. Can be.
[0056]
Next, according to the embodiment in which the notch 28A is formed in the pressing member 28, even if the measuring tube is deformed by welding or the like, the upper and lower portions of the pressing member can easily contact the measuring tube. Can be done.
[0057]
Next, according to the embodiment in which the length from the lower surface of the support 21 to the lower side of the portion of the pressing member 28 in contact with the measurement tube 20 is 200 mm or more, the fluid vibration stress generated in the measurement tube is further reduced. be able to.
[0058]
According to the embodiment in which the first wedge member 27 has the pin 38 and the second wedge member 32 has the pin 45, the wedge member can be moved up and down by turning the tightening bolt. it can.
[0059]
【The invention's effect】
According to the present invention, since the measurement tube is held in a sandwiched state, even if fluid vibration is applied from any direction to the welded portion between the support and the measurement tube, the stress due to the vibration can be reduced.
[0060]
As a result, according to the present invention, it is possible to provide a clamp apparatus and a clamp method for a jet pump measurement pipe in which the measurement pipe can be firmly fixed to the diffuser.
[Brief description of the drawings]
FIG. 1 is a top view showing an embodiment of a clamp device for a jet pump measurement pipe according to the present invention.
FIG. 2 is a side view of one embodiment of the present invention.
FIG. 3 is an enlarged top view showing a part of one embodiment of the present invention.
FIG. 4 is a top view of the body according to the embodiment of the present invention.
FIG. 5 is an enlarged side sectional view showing another part of the embodiment of the present invention.
FIG. 6 is a side sectional view showing, on an enlarged scale, still another part of one embodiment of the present invention.
FIG. 7 is a perspective view of a detent member according to an embodiment of the present invention.
FIG. 8 is an explanatory diagram showing an example of a recirculation system in a boiling water reactor.
FIG. 9 is an explanatory view of a conventional jet pump.
FIG. 10 is an explanatory diagram showing an example of a reactor and wells.
FIG. 11 is an explanatory view showing an attachment state of the clamp device according to the embodiment of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 reactor pressure vessel 2 jet pump 3 recirculation pump 4 core 5, 6 coolant 7 lower core plenum 8 riser elbow 9 riser tube 10 transition piece 11 elbow 12 nozzle 13 inlet mixer 14 diffuser 15 bracket 16 support 17 wedge 18 beam 19 riser Brace 20 Measuring tube 21 Measuring tube support 22 Arm 23 Body 24 Projection 25 Suspension fitting 26 Round hole 27 First wedge member 28 Pressing member 29 Groove 30 Tightening bolt 31 Screw hole 32 Second wedge member 33 Detent member 34 Groove 35 Tightening bolt 36 Screw hole 37 Hole 38 Pin 39 Hole 40 Washer 41 Wedge portion 42 Arrow 43 Groove 44 Hole 45 Hole 46 Hole 47 Washer 48 Wedge portion 49 Arrow 50 Projection 51 Projection 52 Reactor well 53 Water 54 Fuel exchange truck 55 Rope 56 Handrail 57 Clamping device 58 Hex head 59 Hex head 60 Bent state 61 Bent state 62 Hook-shaped hook

Claims (11)

In a clamp device of a jet pump measurement tube for clamping a measurement tube for flow measurement attached via a support to a diffuser of a jet pump installed in a reactor pressure vessel,
A C-shaped arm in contact with the outer surface of the diffuser;
A body provided at one end of the arm,
A first wedge member movably held on the body via a fastening bolt;
A pressing member having one end engaged with the first wedge member and the other end contacting the outer surface of the measurement tube;
A second wedge member movably held on the body via a fastening bolt;
A detent member having one end engaged with the second wedge member and the other end abutting against the outer surface of the measurement tube,
The pressing member is abutted on a surface of the measurement tube having the support opposite to the support,
The detent member is abutted on a surface of the measuring tube having the support on the same side as the support,
A clamp device for a jet pump measurement tube, characterized in that the measurement tube is clamped while being sandwiched. The clamp device for a measuring pipe for a jet pump according to claim 1,
A clamp device for a jet pump measuring pipe, wherein at least one round hole is formed in the C-shaped arm. The clamp device for a measuring pipe for a jet pump according to claim 1,
A jet pump measuring pipe, comprising: at least one hanging fitting having a hole opened in the same direction as the curvature of the arm on one upper surface of the C-shaped arm and the body. Clamping device. The clamp device for a measuring pipe for a jet pump according to claim 1,
A part of the C-shaped arm which is in contact with the diffuser is provided with two protrusions arranged with an opening of 90 degrees or more and 100 degrees or less with respect to the center of the diffuser, wherein a jet pump measurement pipe is provided. Clamping device. The clamp device for a measuring pipe for a jet pump according to claim 1,
A clamp device for a jet pump measurement pipe, wherein the detent member is provided with a tip portion abutting on a lower surface of the support. The clamp device for a measuring pipe for a jet pump according to claim 1,
A clamp device for a jet pump measuring pipe, wherein a hook-shaped hook abutting on a side surface of the support is provided on the detent member. The clamp device for a measuring pipe for a jet pump according to claim 1,
The detent member is provided with members located on the upper and lower surfaces of the support,
The member on the upper surface of the support is longer than the member of the support. The clamp device for a measuring pipe for a jet pump according to claim 1,
A notch is formed at an intermediate portion of the pressing member in contact with the outer surface of the measurement tube, and a clamp device for a jet pump measurement tube is provided. The clamp device for a measuring pipe for a jet pump according to claim 1,
A length from a lower surface of the support to a lower side of a portion of the pressing member contacting the measurement pipe is 200 mm or more, wherein a clamp device for a jet pump measurement pipe is provided. The clamp device for a measuring pipe for a jet pump according to claim 1,
The first wedge member and the second wedge member are provided with a pin adjacent to the tightening bolt for preventing the tightening bolt from coming off. A method for clamping a jet pump measurement pipe using the jet pump measurement pipe clamping device according to any one of claims 1 to 10,
Of the first wedge member and the second wedge member, first, the pressing member is pressed against the measurement tube by the first wedge member, and then the detent member is pressed by the second wedge member. A method of clamping a jet pump measuring pipe, characterized by being attracted to the measuring pipe.

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