JP4047729B2 - Clamping apparatus and clamping method for jet pump measuring tube - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a measuring tube for measuring the flow rate of a jet pump in a pressure vessel of a boiling water reactor, and more particularly, to a measuring tube clamping device and a clamp attached to a jet pump diffuser via a support. Regarding the method.
[0002]
[Prior art]
A boiling water reactor has a recirculation system in its pressure vessel. A jet pump is used for this recirculation system. An example of such a boiling water reactor recirculation system will be described with reference to FIG.
[0003]
Here, in FIG. 8, 1 represents a reactor pressure vessel, and a plurality of jet pumps 2 are provided so as to surround the core 4 in the reactor pressure vessel, whereby the reactor recirculation system together with the recirculation pump 3 is provided. , And a coolant (reactor water) having a flow rate necessary for changing the output of the nuclear reactor is supplied to the core 4.
[0004]
At this time, a part of the coolant 5 forcibly circulating in the reactor core 4 is taken out of the reactor pressure vessel 1 and is pressurized by the recirculation pump 3 and then becomes driving water at high speed 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, and sent to the lower core plenum 7 for recirculation.
[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 measurement tube, and 21 is a measurement tube support.
[0006]
Here, the measuring pipe 20 is installed to transmit the pressure in the diffuser 14 to a differential pressure gauge provided outside the reactor pressure vessel and measure the flow rate. For this reason, the measuring pipe support 21 In this case, in the prior art, a clamp device is attached to the measurement tube, and the measurement tube is restrained from two directions (see, for example, Patent Document 1). ).
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-90085
[Problems to be solved by the invention]
A jet pump is installed in a reactor coolant in a nuclear reactor, and a high-speed fluid flows inside the reactor. Therefore, the jet pump is affected by fluid vibrations from the fluid inside and outside. Then, this vibration is transmitted to the measurement tube. At this time, if the frequency of this vibration matches the natural vibration frequency of the measurement tube, the load acting on the measurement tube is increased by resonance, and the measurement tube itself and the measurement tube And there is a possibility of damaging the welded part of the measuring tube support.
[0009]
Here, if damage occurs, the method of repairing the measurement pipe may be by welding or mechanical joints, but this repair work is underwater work, and the repair equipment becomes large, and The repair work will take a long time.
[0010]
Therefore, it is necessary to prevent damage to the measurement tube itself or the welded portion of the measurement tube and the measurement tube support. The problem remained in securing.
[0011]
Here, although the above-mentioned conventional technique attaches a clamp device to the measurement tube, at this time, the measurement tube is restrained from two directions, and therefore, when the load acting on the measurement tube increases due to resonance. There remains a problem with reliability.
[0012]
The present invention has been made to solve the above-mentioned problems, and its purpose is to reduce stress caused by fluid vibrations applied to the support of the diffuser and the welded portion of the measuring tube from all directions. Another object of the present invention is to provide a clamping device and a clamping method for a jet pump measuring tube.
[0013]
[Means for Solving the Problems]
The above-described object is to provide a jet pump measuring tube clamping device that clamps a flow rate measuring tube attached to a jet pump diffuser installed in a reactor pressure vessel via a support, in contact with the outer surface of the diffuser. Shaped arm, a body provided at one end of the arm, a first wedge member movably held on the body via a fastening bolt, and one end engaged with the first wedge member Is pressed against the outer surface of the measuring tube, a second wedge member movably held on the body via a clamping bolt, and one end engaged with the second wedge member and the other end A retaining member that abuts against the outer surface of the measuring tube, and the pressing member is abutted against the surface opposite to the support in the portion having the support of the measuring tube. 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, even if at least one round hole is formed in the C-shaped arm, the above-described object can be achieved, and a hole is formed on the upper surface of the C-shaped arm and the body in the same direction as the curvature of the arm. The above-mentioned object can also be achieved by providing at least one suspension metal fitting having an opening in the portion of the C-shaped arm in contact with the diffuser at 90 degrees or more with respect to the center of the diffuser. The above object can also be achieved by providing two protrusions arranged with an opening of less than 1 degree.
[0015]
Further, at this time, the holding member may be provided with a tip portion that is provided on the lower surface of the support. At this time, the holding member is provided with a hook-shaped hook that is provided on the side surface of the support. In this case, the retaining member is provided with members positioned 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, and this In some cases, a notch portion may be formed in an intermediate portion of the portion of the pressing member that contacts 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, the first wedge member and the second wedge member, A pin for preventing the tightening bolt from coming off may be provided adjacent to the tightening bolt.
[0017]
On the other hand, in the jet pump measuring tube clamping method using any one of the jet pump measuring tube clamping devices described above, the first of the first wedge member and the second wedge member is the first one. The above object can also be achieved by pressing the pressing member against the measuring tube with the wedge member and then pulling the holding member against the measuring tube with the second wedge member.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a jet pump measuring tube clamping device according to the present invention will be described in detail with reference to embodiments shown in the drawings. Here, FIG. 1 is a top view of an embodiment of the present invention, FIG. 2 is a side view, FIG. 3 is an enlarged top view of part a in FIG. 1, and FIG. 4 is a top view of only the body in FIG. 5 and 6 are side views in which the portion b in FIG. 2 is enlarged and further partially cut away, and FIG. 7 is a three-dimensional view of the 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 a body 23 is provided at one end of the arm 22. The diffuser 14, the measurement tube 20, and the measurement tube support 21 are as described in the prior art.
[0020]
Further, as shown in FIG. 1, the arm 22 has protrusions inwardly at two points, that is, a tip part and a part of the tip part that is opened 100 degrees from the center of the diffuser 14 with respect to the tip part. 24, and these protrusions 24 come into contact with the outer surface of the diffuser 14, so that the arm 22 is brought into contact with the diffuser 14 at almost two points and is accurately held.
[0021]
If the angle formed by the two protrusions 24 at this time is large, the bending stress acting on the arm 22 becomes too strong when the arm 22 described later supports the diffuser 14 at three points, and if it is small, the lateral positioning is sufficient. In practical use, it is desirable to set the angle between 90 degrees and 100 degrees.
[0022]
Furthermore, suspension brackets 25 are provided on the upper surfaces of the arms 22 and the body 23, and these suspension brackets 25 are arranged in the arc direction of the arms 22 as clearly shown in FIG. A hole 25a for passing a rope for hanging down that is opened in the same direction is provided, and the rope that has 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 can be prevented from doing.
[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 hanging bracket 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 specifically shown 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 fastening bolt 35 is screwed are provided.
[0025]
At this time, as shown in FIG. 5, a notch 28 </ b> A is formed in an intermediate portion of the portion where the pressing member 28 is in contact with the measuring tube 20, so that the measuring tube 20 is bent. In addition, the pressing member 28 can be contacted at the top and bottom of the portion in contact with the measuring tube 20.
[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, thereby measuring the tube 20. It is possible to further reduce the fluid vibration stress generated in.
[0027]
Here, as shown in FIG. 5, the first wedge member 27 is provided with a hole 37 into which the tightening bolt 30 is inserted, and a hole 39 into which the pin 38 is inserted is formed above the hole 37. And orthogonal to each other. The pin 38 connects the first wedge member 27 and the tightening bolt 30. When the tightening bolt 30 is rotated by the pin 38, the tightening bolt 30 and the first wedge member 27 simultaneously move up and down. To do.
[0028]
A washer 40 for preventing loosening after tightening is provided on the upper portion of the tightening bolt 30 so as to be integrated with the tightening bolt 30. Although not shown, a washer is used using a dedicated device. 40 is bent to prevent loosening after tightening.
[0029]
Although not shown in the drawing, the tip of the first wedge member 27 is provided with a groove in the shape of a kana character, and a protrusion in the shape of a kana character provided in the pressing member 28. When the fastening bolt 30 is rotated by this fitting (not shown), the wedge portion 41 of the first wedge member 27 moves up and down, and the first wedge member 27 is engaged 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, and a hole 46 into which the pin 45 is inserted is formed above the hole 44. Provided perpendicular 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 simultaneously move up and down.
[0033]
At this time, a washer 47 for preventing looseness after tightening is provided on the upper portion of the tightening bolt 35 integrally with the tightening bolt 35. Although not shown, the washer 47 is bent using a dedicated device so that loosening after tightening can be prevented.
[0034]
In addition, although not shown in the drawing, a groove in the shape of a Kana character is formed at the tip of the second wedge member 32, and this is a Kana character in the shape of the retaining member 33. When the projection bolt (also not shown) is fitted and thereby the tightening bolt 35 is rotated, the wedge portion 48 of the second wedge member 32 moves up and down, and the second wedge member 32 is moved up and down. As shown by the arrow 49, the retaining member 33 fitted to is moved left and right.
[0035]
As shown in FIG. 7 in particular, the retaining member 33 is L-shaped as a whole, and the L-shaped tip is divided into upper and lower portions to form tip portions 50 and 51. The tip portions 50 and 51 are in contact with the measuring tube 20, but the tip portion 50 is further longer than the tip portion 51.
[0036]
As a result, the lower end 51 is in contact with the lower surface of the support 21, thereby preventing the entire clamping device 57 from being lifted by the taper of the diffuser 14. The letter-shaped tip 51 is provided with a hook-shaped hook 62 directed upward at the tip so that the movement of the clamping device 57 in the rotational direction can be prevented.
[0037]
Next, the procedure for attaching the clamping 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 reactor containment vessel lid and the reactor pressure vessel 1 lid are first removed. Thereafter, after filling the reactor well 52 with water 53, the steam dryer and the steam separator in the reactor pressure vessel 1 are removed.
[0038]
In this state, the work for attaching the clamp device 57 to the measuring tube is performed. At this time, first, as shown in FIG. 10, on the fuel change carriage 54 or on the work carriage not shown. After passing the rope 55 through the hanging metal fitting 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, the rope 55 may be passed through the hole 26 of the arm 22 for those in which the movement of the clamping device 57 is difficult.
[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. To do.
[0040]
The method of installing in the predetermined position at this time first places the tip 50 of the retaining member 33 on the support 21 and then turns the clamp device 57. At this time, since the tip 50 is longer than the tip 51, provisional setting can be facilitated.
[0041]
Next, the plurality of ropes 55 are pulled upward, the entire clamping 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, using an operation pole having a hexagon socket wrench at the tip, the hex socket at the tip is inserted into the hex head 58 (FIG. 5) at the head of the tightening bolt 30, When the tightening bolt 30 is rotated to the right, the first wedge member 27 is lowered, and the pressing member 28 moves in the direction of the diffuser 14, so that the U-shaped groove 43 at the distal end of the retaining member 28. , The diffuser 14, the measurement tube 20, and the clamp device 57 are integrally fixed.
[0043]
Next, although not shown in the figure, the hexagon socket at the tip of the operation pole is inserted into the hexagon head 59 (FIG. 6) of the head of the tightening bolt 35 and rotated to the right to rotate the tightening bolt 35. As a result, the second wedge member 32 is lowered and the retaining member 33 moves toward the measuring tube 20, whereby the L-shaped tip portions 50 and 51 of the retaining member 33 are further attached to the measuring tube 20. Adhere strongly.
[0044]
Thereafter, a washer folding device (not shown) is lowered from the carriage 54, and the washers 40 and 47 provided integrally with the fastening bolts 30 and 35 are folded. The folded states 60 and 61 are shown in FIG. In this state, the tightening bolts 30 and 35 are prevented from loosening.
[0045]
Then, in 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 extremely firmly.
[0046]
At this time, the clamping device 57 itself has two projections 24 provided on its C-shaped arm 22 abutting on one side of the diffuser 14 at an angle of 100 degrees, for example, On the body 23 side, the pressing member 28 is pressed against the opposite side of the diffuser 14 through the measuring tube 20 and the support 21 by the wedge action of the first wedge member 27, and this is applied to the diffuser 14 at three points. It will be held firmly.
[0047]
Therefore, according to this embodiment, the stress applied to the measuring tube 20 can be reliably reduced regardless of the direction of the stress due to the fluid vibration of the diffuser 14, and as a result, the safety of the plant can be improved and stable operation can be ensured. it can.
[0048]
Here, it will be as follows if the effect by the said embodiment is enumerated.
[0049]
According to the above embodiment, the stress that appears due to fluid vibration in the measurement pipe of the jet pump can be reduced, and the effect of preventing damage to the measurement pipe 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 by passing the rope through the round hole when attaching the clamp device. Easy to install.
[0051]
Next, according to the embodiment in which the C-shaped arm 22 is provided with the hanging metal fitting 25, 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 contact with the outer surface of the diffuser accurately. be able to.
[0053]
Next, according to the embodiment in which the holding member 33 is provided with the tip portions 50 and 51, there is no possibility that the clamp device is lifted from the initially set position during operation of the plant, so that the set position is surely maintained. be able to.
[0054]
Next, according to the embodiment having the hook-shaped hook 62 in the retaining member 33, there is no fear that the clamp device rotates during the plant operation, so that the set position can be reliably maintained.
[0055]
Next, according to the embodiment in which the holding member 33 includes 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 clamping device can be easily performed. Can do.
[0056]
Next, according to the embodiment in which the notch portion 28A is formed in the pressing member 28, the upper and lower portions of the pressing member are easily brought into contact with the measuring tube even if the measuring tube is deformed by welding or the like. Can be made.
[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 measuring tube is held in a sandwiched manner, the stress caused by the fluid vibration applied to the support and the welded portion of the measuring tube can be reduced.
[0060]
As a result, according to the present invention, it is possible to provide a clamping device and a clamping method for a jet pump measuring tube that can firmly fix the measuring tube to the diffuser.
[Brief description of the drawings]
FIG. 1 is a top view showing an embodiment of a clamping device for a jet pump measuring tube according to the present invention.
FIG. 2 is a side view of an embodiment of the present invention.
FIG. 3 is an enlarged top view showing a part of an embodiment of the present invention.
FIG. 4 is a top view of a body in one 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 an enlarged side sectional view showing still another part of the embodiment of the present invention.
FIG. 7 is a perspective view of a retaining member in one 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 diagram of a conventional jet pump.
FIG. 10 is an explanatory diagram showing an example of a nuclear reactor and a well.
FIG. 11 is an explanatory view showing a mounting state of the clamp device according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Reactor pressure vessel 2 Jet pump 3 Recirculation pump 4 Core 5 and 6 Coolant 7 Lower core plenum 8 Riser elbow 9 Riser pipe 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 Protrusion 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 Anti-holding 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 Protrusion 51 Protrusion 52 Reactor well 53 Water 54 Fuel change carriage 55 Rope 56 Handrail 57 Clamping device 58 Hexagon head 59 Hexagon head 60 Bent state 61 Bent state 62 Saddle hook

Claims (11)

In the clamp device of the jet pump measuring tube that clamps the measuring tube for flow measurement attached to the diffuser of the jet pump installed in the reactor pressure vessel via the support,
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 tightening bolt;
A pressing member whose one end is engaged with the first wedge member and whose other end is in contact with the outer surface of the measurement tube;
A second wedge member movably held on the body via a tightening bolt;
A retention 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 brought into contact with a surface opposite to the support in the portion having the support of the measurement tube,
The retaining member is brought into contact with a surface on the same side as the support in the portion having the support of the measurement tube,
A jet pump measuring tube clamping device, wherein the measuring tube is clamped in a sandwiched state. In the clamping device of the measuring pipe for jet pumps according to claim 1,
A jet pump measuring tube clamping device, wherein at least one round hole is formed in the C-shaped arm. In the clamping device of the measuring pipe for jet pumps according to claim 1,
The upper surface of one of the C-shaped arm and the body is provided with at least one suspension fitting having a hole opened in the same direction as the arc direction of the C-shaped arm. Jet pump measuring tube clamping device. In the clamping device of the measuring pipe for jet pumps according to claim 1,
A jet pump measuring pipe characterized in that two projections arranged with an opening of 90 degrees or more and 100 degrees or less with respect to the center of the diffuser are provided in a portion of the C-shaped arm in contact with the diffuser. Clamping device. In the clamping device of the measuring pipe for jet pumps according to claim 1,
Wherein the member for holding back, the clamping device of the jet pump instrumentation tube, wherein a distal end portion which abuts the lower surface of the support is provided. In the clamping device of the measuring pipe for jet pumps according to claim 1,
The jet pump measuring tube clamping device according to claim 1, wherein a hook-shaped hook provided on a side surface of the support is provided on the retaining member. In the clamping device of the measuring pipe for jet pumps according to claim 1,
When the clamping device is temporarily set to the retaining member, an upper member that comes into contact with the upper surface of the support and a lower member that comes into contact with the lower surface are provided in the retaining member ,
The jet pump measuring tube clamping device, wherein the upper member is longer than the lower member. In the clamping device of the measuring pipe for jet pumps according to claim 1,
A jet pump measuring tube clamping device, wherein a notch portion is formed in an intermediate portion of the pressing member in contact with the outer surface of the measuring tube. In the clamping device of the measuring pipe for jet pumps according to claim 1,
The jet pump measuring tube clamping device, wherein a length from a lower surface of the support to a lower side of a portion of the pressing member in contact with the measuring tube is 200 mm or more. In the clamping device of the measuring pipe for jet pumps according to claim 1,
A jet pump measuring tube clamping device, wherein the first wedge member and the second wedge member are provided with a pin adjacent to the fastening bolt to prevent the fastening bolt from coming off. In the method of clamping a jet pump measurement tube using the clamp device for a jet pump measurement tube 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 measuring tube by the first wedge member, and then the retaining member is moved by the second wedge member. A method of clamping a jet pump measuring tube, characterized by being attracted to the measuring tube.

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