JPH10186080A - Jet pump clamp device and its handling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the stress generated by fluid vibration at a weld section between a riser pipe and a thermal sleeve by opening a half-split ring coupled with the upper and lower rings by their coupling recess and projection with a fastening bolt. SOLUTION: When a fastening bolt 60 is loosened, the screw section of the fastening bolt 60 is lifted against the screw hole of an upper ring 51, an opening/ closing block 59 is lifted, and an opening section is formed at one end of a half-split ring 50. When a fastening bolt 56 is loosened and lifted from a female collar 58, the upper ring 51 is separated from a lower ring 52, and the opening section is further increased. Since the coupling recess 54 of the upper ring 51 is coupled with the coupling projection 55 of the lower ring 52, the upper ring 51 is surely guided and vertically lifted. The half-split ring 50 is inserted into a welding part between a riser pipe 12 and a thermal sleeve 29. The stress generated by fluid vibration at the welding part can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a weld between a riser pipe of a jet pump installed in a reactor pressure vessel of a boiling water reactor (BWR) and a thermal sleeve connected to the riser pipe. The present invention relates to a jet pump clamp device used for reducing stress caused by generated fluid vibration and a handling device thereof.

[0002]

2. Description of the Related Art Conventionally, a BWR employs a so-called jet pump system in which a recirculation pump installed outside a reactor pressure vessel and a jet pump installed inside the reactor pressure vessel are combined to increase the power density. ing. Hereinafter, BW using this jet pump system
The R jet pump will be described.

A conventional example will be described with reference to FIGS. FIG. 16 is a longitudinal sectional view showing a schematic configuration of the BWR. As shown in FIG. 16, a coolant 2 and a reactor core 3 are accommodated in a reactor pressure vessel 1. The reactor core 3 is composed of a plurality of fuel assemblies and control rods (not shown). Is housed in

[0004] The coolant 2 flows upward through the reactor core 3, and at this time, the temperature thereof is increased by the nuclear reaction heat of the reactor core 3, and a two-phase flow of water and steam is formed. The coolant 2 in the two-phase flow state flows into the steam separator 4 installed above the reactor core 3, where it is separated into water and steam. Of these, the steam is introduced into a steam dryer 5 installed above the steam separator 4, and becomes dry steam.

[0005] The dried steam is transferred to a steam turbine (not shown) via a main steam pipe 6 connected to the reactor pressure vessel 1 and is used for power generation. On the other hand, the separated water is
The gas flows through the downcomer portion 7 between the reactor and the reactor pressure vessel 1 and flows down below the reactor core 3. A control rod guide tube 8 is provided below the core 3, and a control rod is inserted into or pulled out of the core 3 via the control rod guide tube 8. A control rod drive mechanism 9 is provided below the control rod guide tube 8, and the control rod drive mechanism 9 controls the insertion and withdrawal of control rods into and from the reactor core 3.

In the downcomer section 7, a jet pump 1 is provided.
1 are installed at equal intervals in the circumferential direction, while a recirculation pump (not shown) is installed outside the reactor pressure vessel 1.
A recirculation system is constituted by the recirculation piping disposed between the two. Driving water is supplied to the jet pump 11 by the recirculation pump, and the coolant 2 is forcibly circulated into the core 3 by the action of the jet pump 11.

[0007] The jet pump 11 has a riser tube 12 as shown in FIG. 17 in which the main part of FIG. 16 is enlarged, and this riser tube 12 is fixed to the reactor pressure vessel 1.
The coolant 2 supplied from the recirculation inlet nozzle 13 of the recirculation pump is introduced into the furnace. In the upper part of the riser tube 12,
A pair of elbows 15 via the transition piece 14
(15A, 15B) are connected.

A pair of inlet throats 17 (17A, 17B) are connected to the elbows 15A, 15B via a pair of mixing nozzles 16 (16A, 16B). This pair of inlet throats 17A, 1
7B includes diffusers 18 (18A, 18A), respectively.
B) is connected.

[0009] The coolant 2 is injected by the mixing nozzles 16A and 16B. At that time, the reactor water is entrained from the surroundings, and the injected coolant 2 and the entrained water are
They are mixed in the inlet throats 17A and 17B, respectively. Thereafter, the hydrostatic head is restored by the diffusers 18A and 18B.

By the way, in the above configuration, fluid vibration is generated by the flow of the coolant sent from the recirculation pump. In order to cope with this fluid vibration, riser pipe 1
As described above, the lower end 2 is welded to the recirculation inlet nozzle 13, and the upper end is fixed to the reactor pressure vessel 1 via the riser brace 20.

Also, inlet throats 17A and 17B
As described above, the upper ends thereof are mixed nozzles 16A and 16A.
B, and mechanically connected to the transition piece 14 via the bend, the lower end of which is inserted into the upper ends of the diffusers 18A, 18B. Thus, the riser tube 12 and the inlet throats 17A, 17B
Are configured to sufficiently cope with fluid vibration.

Next, the configuration above the mixing nozzles 16A and 16B will be described.
A pair of ears 21 is formed on both sides of the head, and these ears 21 project upward, and a groove 22 is formed inside the upper end thereof. In this groove 22,
A pair of jet pump beams 23 having a rectangular cross section that increases along the center in the length direction are fixed by fitting both ends to the groove 22.

At the center of the jet pump beam 23, a screw hole (not shown) is formed in a vertical direction, and a head bolt 24 is screwed into the screw hole. A hexagonal head is formed at the upper end of the head bolt 24, and a semi-round head is formed at the lower end. On the other hand, elbows 15A, 1
5B, a pedestal portion (not shown) having a horizontal upper end surface is formed, and a counterbore (not shown) is formed in this pedestal portion. The semi-round head of the head bolt 24 is fitted into the counterbore via a spherical washer.

The inlet throats 17A and 17B
Is not fixed to the reactor pressure vessel 1, the inflow pressure of the driving water supplied via the riser pipe 12 acts on the upper end and the elbows 15 </ b> A and 15 </ b> B. In addition, a reaction force such as a jet pressure of driving water jetted from the nozzle (not shown) connected to the other ends of the elbows 15A and 15B into the diffusers 18A and 18B acts upward. A head bolt 24 is screwed to the jet pump beam 23 to oppose this load.

Since the ear portion 21 is fixed at a fixed position, when the head bolt 24 is screwed, the head bolt 24 is moved above the jet pump beam 23, and both ends thereof contact the upper wall surface of the groove portion 22. It will be in contact. Thereby, an upward load is received.

Conversely, a downward load is applied to the upper ends of the elbows 15A and 15B via the head bolts 24, and the magnitude thereof is determined in relation to an upward load due to the reaction force of the driving water. Is done. A keeper (not shown) is detachably fitted to the hexagonal head of the head bolt 24.
The keeper is fixed on a support plate (not shown) by spot welding. This support plate has a rectangular shape and is fixed to the upper surface of the jet pump beam 23 with two bolts.

The inlet throats 17A and 17B are attached to a riser blanket 25 fixed to the riser tube 12. Diffusers 18A and 18B
Are fixed to a shroud support (baffle plate) 26 welded to the reactor pressure vessel 1.

The jet pump 11 is used under a severe condition to circulate the coolant, as compared with other devices. Therefore, a large load acts on each member, and severe stress acts particularly on the riser brace 20 that supports the riser tube 12 in the middle.

The riser brace 20 is connected to the riser tube 12.
Of the fluid vibration during the operation of the reactor during the operation of the reactor, and absorbs the difference in thermal expansion between the reactor pressure vessel 1 made of carbon steel and the riser pipe 12 made of austenitic stainless steel. Therefore, during the operation of the reactor, the reactor is in a deformed state while absorbing the difference in thermal expansion.

In controlling the output of a nuclear power plant, it is important to measure the flow rate of the jet pump during normal operation. For this reason, the diffusers 18A, 18B
A measuring pipe 19 is provided in the upper and lower portions of the diffuser 18 to measure a static pressure difference between the upper and lower portions of the diffuser 18 during operation, and a jet pump flow rate is calculated based on the measured value and a calibration value measured before using the plant.

The measuring pipe 19 is welded to the static pressure holes at the upper and lower portions of the diffuser 18, is welded and supported by a support 27 fixed to the diffuser 18, and is arranged in a complicated state below the jet pump 11.
It is connected to the piping outside the furnace via a nozzle for jet pump measurement.

The nozzles for measuring the jet pump are provided at two target positions in the reactor pressure vessel 1. The jet pump 11 having such a configuration is used under severe conditions compared to other devices due to the flow at the time of cooling sent from the recirculation pump. For this reason, a large load acts on each member, which is affected by the fluid vibration, and a severe stress acts. Therefore, it is sufficiently expected that pipe breakage will occur.

[0023]

In the above structure, if a crack or a break occurs in the jet pump system body or a welded portion due to any cause, the repair work is performed in a high radiation control area. It needs to be performed remotely from directly above the core. Therefore, it is extremely difficult to access the piping.

As a repairing means for the jet pump 11 broken as described above, welding can be considered. However, since the repairing work is generally performed underwater, a large-scale repairing device is required. There is also a problem of long-term construction.

Also, if these works are left unchecked, there is a possibility that the jet pump 11 will progress further and cracks will occur, and the jet pump 11 for controlling the output of the nuclear reactor will be in such a state. This may adversely affect other structures, which is not preferable.

The present invention has been made in view of the above-described circumstances, and is directed to a jet pump capable of reducing stress caused by fluid vibration generated at a weld between a lower portion of a riser pipe of a jet pump and a thermal sleeve connected to the riser pipe. It is an object to provide a pump clamp device.

Another object of the present invention is as follows.
An object of the present invention is to provide a handling device for a jet pump clamp device that can easily attach the jet pump clamp device to a weld between a lower portion of a riser pipe of a jet pump and a thermal sleeve.

[0028]

In order to solve the above-mentioned problems, a first aspect of the present invention is to reduce a stress caused by fluid vibration generated at a welded portion of a riser pipe of a jet pump installed in a reactor pressure vessel. In a jet pump clamp device for reducing the pressure, a two-part ring abutting on the outer periphery of a welded portion between the lower part of the riser pipe and a thermal sleeve connected to the riser pipe, and an engagement recess in one of the two-part rings An opening / closing guide formed on the other side and having an engaging projection engaged with the engaging recess; and a tightening bolt attached to the opening / closing guide for opening and closing the two-piece ring. Features.

A second aspect of the present invention is characterized in that the opening of the two-piece ring according to the first aspect is formed in the same shape as the outer peripheral surface of the lower portion of the riser tube.

A third aspect of the present invention relates to a jet pump clamp apparatus for reducing stress caused by fluid vibration generated at a welded portion of a riser pipe of a jet pump installed in a reactor pressure vessel. An upper plate inserted between the core shroud of the vessel and a pressing member for pressing the upper plate between the riser tube and the core shroud are provided.

According to a fourth aspect of the present invention, there is provided the jet pump clamping apparatus according to the third aspect, wherein a plurality of long rods each having one end connected to the upper plate by a pin, and the other end of each of the long rods being connected to each other by a pin. And a lower plate supported by a baffle plate of the jet pump, wherein the upper plate, a plurality of long rods and the lower plate constitute a parallel link mechanism.

According to a fifth aspect of the present invention, in the jet pump clamp device according to the third or fourth aspect, when the parallel link mechanism is closed by the pin connecting the upper plate and the plurality of long rods, the closing adjustment is limited. A stopper is provided.

According to a sixth aspect of the present invention, in the jet pump clamp device according to the third or fourth aspect, a hanging ear is attached to the upper plate, and when the hanging ear is lifted, the parallel link mechanism is closed by its own weight while the hanging ear is closed. And the parallel link mechanism is opened when the lower plate is seated on the baffle plate by suspending the lower plate.

According to a seventh aspect of the present invention, in the jet pump clamp apparatus according to the fourth aspect, at least one support is provided at an axially intermediate portion of the plurality of long rods, and the plurality of long rods are atomized through the support. The furnace pressure vessel is supported by a core shroud.

In a jet pump clamping apparatus for reducing stress caused by fluid vibration generated at a welded portion of a riser pipe of a jet pump installed in a reactor pressure vessel, a lower portion of the riser pipe and this riser are provided. A two-part ring abutting on the outer periphery of the welded portion with the thermal sleeve connected to the pipe; and an engaging projection that forms an engagement recess on one of the two rings and engages the engagement recess on the other side An opening / closing guide portion, a tightening bolt attached to the opening / closing guide portion for opening and closing the two-piece ring, and an upper plate interposed between the riser tube and a core shroud of the reactor pressure vessel. A pressing member for pressing the upper plate between the riser tube and the core shroud, the two-part ring and the upper plate Characterized in that a connecting arm for connecting.

A ninth aspect of the present invention is directed to a jet pump clamp apparatus for reducing a stress caused by fluid vibration generated at a welded portion of a riser pipe of a jet pump installed in a reactor pressure vessel. A support block interposed between the core shroud of the container and a support bolt attached to the support block via a tightening bolt to press the support block between the riser tube and the core shroud by tightening the tightening bolt; And a pressing wedge.

According to a tenth aspect, in the jet pump clamp device according to the ninth aspect, a grip lever for gripping the riser pipe is provided on the support block.

According to a eleventh aspect of the present invention, there is provided a jet pump clamping apparatus for handling a jet pump clamp apparatus for reducing stress caused by fluid vibration generated at a welded portion of a riser pipe of a jet pump installed in a reactor pressure vessel. A handling device for a clamping device, comprising: a holding member that holds an open state of a two-part ring that can abut on an outer periphery of a welded portion between a lower portion of the riser tube and a thermal sleeve connected to the riser tube; A swing drive unit provided on the holding member for rotating the holding member; a suspension plate attached to the swing drive unit; and an extrusion drive unit provided on the holding member and extruding the two-piece ring. And

[0039]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a first embodiment of a jet pump clamp device according to the present invention, and FIG.
FIG. 3 is a sectional view taken along line A-B of FIG. 1. The structures of the reactor pressure vessel and the jet pump are shown in FIG.
6 and FIG. 17, and the description will be made using the same reference numerals.

The jet pump clamp device according to the present invention is a jet pump clamp device installed in a reactor pressure vessel 1.
The elbow 28 at the lower part of the riser tube 12 and the elbow 28
This is to reduce stress due to fluid vibration generated at a welded portion with the thermal sleeve 29 connected to the thermal sleeve 29.

As shown in FIG. 1, in the first embodiment, a parallel link mechanism 30 inserted between the riser pipe 12 and the core shroud 10 of the reactor pressure vessel 1 to prevent the riser pipe 12 from vibrating. And a two-part ring 50 that abuts on the outer periphery of the weld between the elbow 28 and the thermal sleeve 29 at the lower part of the riser pipe 12 and reduces the stress caused by fluid vibration generated at this weld. Is composed.

The parallel link mechanism 30 is connected to the upper plate 3 inserted between the riser tube 12 and the core shroud 10.
1, a plurality of (four) long rods 33 each having one end connected to the upper plate 31 by a pin 32, and a baffle of the jet pump 11 connected to the other end of each of the long rods 33 by a pin 34. And a lower plate 35 supported by the plate 26.

As shown in FIG. 2, the upper plate 31 has an arcuate surface portion 36 having the same radius of curvature as the riser tube 12 on one side surface.
Are formed so that three springs 37 as pressing members protrude from the arc surface portion 36 to the riser tube 12, and these springs 37 press the riser tube 12, thereby causing the upper plate 31 to move the riser tube 12. Between the outer peripheral surface of the core shroud 10 and the outer wall surface of the core shroud 10 to maintain the horizontal load of the elbow 28 below the riser tube 12;
The thermal expansion of the riser tube 12 and the core shroud 10 is absorbed, and the impact is reduced.

As described above, one end of the long rod 33 is rotatably connected to the upper plate 31 by the four pins 32, and two pins 38 of the four pins 32 are parallel links. When the mechanism 30 is closed, it has a function as a stopper for limiting the degree of closing.

Further, the upper plate 31 is provided with hanging ears 39 near both ends in the longitudinal direction. When the hanging ears 39 are lifted, the parallel link mechanism 30 is closed by its own weight, while the hanging ears 39 are hung. Lower plate 35
The parallel link mechanism 30 is configured to open when the user sits on the baffle plate 26. The upper plate 31 is connected to a later-described two-part ring 50 via two connection arms 40.

Each of the four long rods 33 is formed in the shape of a prism, and an intermediate support 41 is connected to an axially intermediate portion thereof by a pin (not shown). The rod 33 is supported on the outer wall surface of the core shroud 10. Although one intermediate support 41 is provided in FIG. 1, the invention is not limited to this, and a plurality of intermediate supports 41 may be provided.

As shown in FIG. 3, the lower plate 35
The other ends of the long rods 33 are rotatably connected to each other by the pins 34 and are formed in a substantially triangular shape. The arc surface portions 42 have the same radius of curvature as the core shroud 10, and the two flat portions 43. When the arc surface portion 42 abuts on the outer wall surface of the core shroud 10 and the two flat portions 43 abut on the diffuser 18, they are fixedly supported so as not to move in the horizontal direction.

Next, the operation of the parallel link mechanism 30 will be described.

The parallel link mechanism 3 configured as described above
The core shroud 1 is closed in a diamond shape by its own weight by lifting the lifting ear 39 as shown in FIG.
When the lower plate 35 is seated on the baffle plate 26, the parallel link mechanism 30 is opened as shown in FIG.

As a result, the lower plate 35 is in a horizontal state, and the outer wall surface of the core shroud 10
And the two flat portions 43 abut against the diffuser 18 and are fixed and supported. On the other hand, the upper plate 31 is also in a horizontal state, and the outer peripheral surface of the riser tube 12 and the outside of the core shroud 10 are moved by three springs 37. It is pressed against the wall. Similarly, the intermediate support 41 is in a horizontal state and
The long rods 33 are supported on the outer wall surface of the core shroud 10.

As a result, fluid vibration generated at the welded portion between the riser pipe 12 and the thermal sleeve 29 by the parallel link mechanism 30 can be reliably and quickly prevented by underwater remote operation with the jet pump 11 installed. .

The upper plate 31 and the long rod 33
When the parallel link mechanism 30 is closed, the long rods 33 come into close contact with each other because the pin 38 that couples the parallel link mechanism 30 has a function as a stopper that limits the degree of closing when the parallel link mechanism 30 is closed. And the opening and closing operation of the parallel link mechanism 30 can be performed smoothly.

FIGS. 5 and 6 show a two-part ring 50, which comes into contact with the outer periphery of the welded portion between the elbow 28 and the thermal sleeve 29 at the lower part of the riser tube 12 as shown in FIG. The purpose of this is to reduce the stress due to the fluid vibration generated in the weld.

The two-part ring 50 has an upper ring 51 and a lower ring 52 as shown in FIG. 5, and one end of the upper ring 51 and the lower ring 52 has a vertical movement guide for opening and closing as shown in FIG. Opening and closing guide 53
The opening and closing guide 53 is provided with an upper ring 51.
And an engagement recess 54 formed at the end of the
Engaging projection 5 formed at the end of lower ring 52
And 5.

The opening / closing guide 53 has a two-part ring 5
A tightening bolt 56 for opening and closing the bolt 0 is attached. The tightening bolt 56 has a flange 57 fixed substantially at the center in the axial direction, and is screwed to a female screw collar 58 fitted to the lower ring 52. An opening / closing block 59 is provided at the other end of the upper ring 51, and the opening / closing block 59 has a tightening bolt 60 and a locking bolt 61.
Is attached.

Further, the opening / closing block 59 has, as shown in FIG. 7, an upper shaft hole 63 into which the upper shaft 62 of the tightening bolt 60 is inserted, a large-diameter hole 65 into which the return member 64 of the locking bolt 61 is inserted. Screw holes 67 for screwing the screw portions 66 of the locking bolts 61 are formed. The upper ring 51 and the lower ring 52 are formed with screw holes 69 and 70 for screwing the screw portions 68 of the tightening bolts 60, respectively.

The upper shaft 62 of the tightening bolt 60 and the screw portion 6
8 is provided with a flange 71 for preventing disengagement, and a fold washer 73 is interposed between an upper surface of the opening / closing block 59 by tightening a nut 72 provided on an upper end portion of the tightening bolt 60.

The folding washer 73 is provided with a locking bolt 61.
The bending member 74 having a slope formed at the bottom is bent downward by the downward movement, the rotation of the tightening bolt 60 is suppressed by this bent portion, and the bent portion of the folding washer 73 is bent to the opposite side by the rise of the return member 64. Will be returned. Reference numeral 75 denotes a stopper, which prevents the upper surface of the bending member 74 from coming off due to contact when the locking bolt 61 is loosened, that is, when it is raised.

On the other hand, the opening of the two-part ring 50, that is, the circular hole 76 formed by the upper ring 51 and the lower ring 52 is formed in the same shape as the outer peripheral surface of the elbow 28 below the riser tube 12. A concave portion 77 is formed in the circular hole 76 so that a welded portion between the riser tube 12 and the thermal sleeve 29 is engaged. Thereby, the two-part ring 50
Is fixed to the elbow 28 without any gap.

Next, the opening and closing operation of the two-piece ring 50 will be described.

The opening operation of the two-part ring 50 is performed by first loosening the tightening bolt 60 and removing the screw portion 68 from the screw hole 70 of the lower ring 52, and then further loosening the tightening bolt 60. Then, the screw portion 68 of the tightening bolt 60 is raised, and the opening / closing block 59 is raised accordingly, so that an opening is formed at the other end of the two-piece ring 50.

Next, when the tightening bolt 56 is loosened and lifted from the female screw collar 58, the upper ring 51 is separated from the lower ring 52, and the opening formed at the other end of the two-part ring 50 is further increased. In this case, the engaging concave portion 54 of the upper ring 51 is
Therefore, the upper ring 51 moves upward in the vertical direction while being reliably guided.

In this manner, the two-piece ring 50 can be inserted into the weld between the riser tube 12 and the thermal sleeve 29. As a result, stress due to fluid vibration generated at the weld between the riser tube 12 and the thermal sleeve 29 can be significantly reduced.

The closing operation of the two-piece ring 50 is performed by alternately tightening the tightening bolts 56 and the tightening bolts 60.
The upper ring 51 is brought into contact with the lower ring 52, and the lower end of the opening / closing block 59 is brought into contact with the lower ring 52 to close the two-part ring 50.
1 by tightening.

The order of mounting the parallel link mechanism 30 and the split ring 50 described above may be any order.
After attaching 0, both are connected via the connecting arm 40.

FIGS. 8 and 9 are a front view and a side view, respectively, showing an embodiment of a handling device for a jet pump clamp device according to the present invention. As shown in FIGS. 8 and 9, the handling device 80 of the jet pump clamp device handles the split ring 50 as the jet pump clamp device. 8 and 9, the surface of the two-piece ring 50 is shown in the opposite direction to FIGS.

The handling device 80 includes a holding frame 81 serving as a holding member for holding an open state of a two-piece ring 50 that can be brought into contact with the outer periphery of the welded portion between the elbow 28 of the riser tube 12 and the thermal sleeve 29. A turning motor 82 provided on the holding frame 81 to turn the holding frame 81 as a turning drive means, a pole 83 attached to the turning motor 82, and a suspension plate 84 connected to the pole 83. , 85 and a cylinder 8 provided as a driving means for pushing out the two-piece ring 50 provided below the holding frame 81.
6 is provided.

Further, at one end of the upper part of the holding frame 81, FIG.
As shown in FIG. 0, a notch groove 87 is formed in which the tightening bolt 56 attached to the two-piece ring 50 is inserted. Notch holes 89 into which the fixing bolts 61 are inserted are respectively formed.

The moving member 9 connected to the cylinder 86 as shown in FIGS.
0 on the moving member 90,
Is supported. Then, by driving the cylinder 86, the moving member 90 moves in the horizontal direction with respect to the holding frame 81, whereby the two-piece ring 50 is pushed out.

Further, the pole 83 and the suspension plates 84 and 85 are three-dimensionally connected to each other at an angle of 90 degrees to form a crank shape. The hanging ears 91 are fixed to the hanging plate 85.

Next, the operation of the handling device 80 will be described.

First, the two-piece ring 50 is set on the holding frame 81 in an opened state. In this state, the holding frame 81 is
As shown in FIG. 1, it is suspended near the diffuser 18 (the position indicated by the dashed line). Next, the rotation motor 82 is driven to rotate the holding frame 81 and move to a position (solid line position) along the inner wall surface of the reactor pressure vessel 1.

Further, as shown in FIG. 8, by driving the cylinder 86, the moving member 90 moves in the horizontal direction with respect to the holding frame 81, thereby pushing out the two-piece ring 50 and engaging with the riser tube 12. Let it. By tightening the tightening bolt 56 and the tightening bolt 60 in this state, the two-part ring 50 is sandwiched between the riser tubes 12.

Then, the two-part ring 50 comes off the holding frame 81. That is, when the tightening bolt 56 and the tightening bolt 60 are tightened, the two-part ring 5
0 is shorter than the holding frame 81 and further tightened, the tightening bolt 56 and the tightening bolt 60
Is also stored in the holding frame 81.

As a result, the tightening bolt 60 is inserted into the notch 8
8, the fastening bolt 56 is pulled out from the notch groove 87, and is released only by moving the holding frame 81 in the horizontal direction. Further, by collecting only the handling device 80, the two-piece ring 50 can be connected to the riser tube 1
2 can be attached.

As described above, according to the handling device 80, the two-part ring 50, which is a jet pump clamp device, can be easily attached to the welded portion between the lower portion of the riser tube 12 and the thermal sleeve 29.

Next, the operation of the jet pump clamp device having the above configuration will be described with reference to FIGS.

FIG. 12 is a configuration diagram showing a suspended state when the jet pump clamp device according to the first embodiment is installed in the reactor pressure vessel 1. As shown in FIG.
In the reactor pressure vessel 1, a cylindrical core shroud 10 is provided.
In the core shroud 10, an upper grid plate 100 supporting an upper end of a fuel assembly (not shown) is provided.
And a core support plate 101 that supports the lower portion of the fuel assembly via a fuel support (not shown). A refueling machine 103 is disposed above the reactor pressure vessel 1.

A pole 105 is suspended from the fuel exchanger 103 via a pole handling mechanism 104. That is, the pole handling mechanism 104 includes the hoist 106 attached to the fuel exchanger 103 and the hoist 1
06, and a wire 105 is connected to the wire 107 via a pole connecting portion 108.
Is connected.

The pole 105 has, for example, a plurality of fixed lengths connected via a pole joint. The parallel link mechanism 30 or the two-piece ring 50 described above is connected to the lower end of the pole 105. Have been.

Next, when the jet pump clamp device of the first embodiment is fixedly held, it is performed in the following order.

First, after shutting down the reactor, the upper lid of the reactor pressure vessel 1 is removed, and then the steam dryer and the shroud head are moved to the equipment storage pool, and thereafter the work is performed. In this case, the parallel link mechanism 30 uses the hoist 106 of the fuel exchanger 103 as shown in FIG.
05 is set at a predetermined position between the core shroud 10 and the riser tube 12 as described above.

In the case of the two-piece ring 50, the pole 105 is operated by the hoist 106 of the fuel exchanger 103, and is suspended and temporarily installed near the diffuser 18 while being held on the holding frame 81 of the handling device 80. Hereinafter, the order of attaching the two-piece ring 50 to the riser tube 12 is as described above. The tightening bolts 56 and 60 are operated by suspending a pole 105 having a nut runner 109 at the lower end thereof with a wire 107 of a hoist 106, and tightening or loosening the nut 105 with the nut runner 109. Furthermore, after attaching the parallel link mechanism 30 and the split ring 50,
These are connected by a connecting arm 40.

As described above, according to the jet pump clamp device of the first embodiment, the stress due to the fluid vibration generated at the welded portion between the lower part of the riser pipe 12 installed in the reactor pressure vessel 1 and the thermal sleeve 29 is reduced. As a result, the operation rate of the plant can be improved.

FIG. 14 is a sectional view showing a second embodiment of the jet pump clamp device according to the present invention. The same parts as those in the first embodiment will be described using the same reference numerals.

As shown in FIG. 14, the jet pump clamp device 110 according to the second embodiment includes a support block 11 inserted between a riser pipe 12 and a core shroud 10.
1 and a pressing wedge 113 that is attached to the support block 111 via a tightening bolt 112 and presses the support block 111 between the riser tube 12 and the core shroud 10 by tightening the tightening bolt 112. I have.

The support block 111 is formed in a plane semicircular shape as shown in FIG. 15, and has a curvature such that the inner peripheral surface thereof substantially matches the radius of curvature of the riser tube 12.
At both ends of the support block 111, the riser pipe 12 is fixed by lever fixing bolts 114 and 114, respectively.
Gripping levers 115, 115 for gripping are mounted. The curvature of the gripping lever 115 is also set to substantially match the radius of curvature of the riser tube 12.

Next, the operation of the jet pump clamp device 110 according to the second embodiment will be described.

The support block 111 is inserted between the riser tube 12 and the core shroud 10, and then the tightening bolt 112 is tightened to push up the pressing wedge 113 to be pressed between the support block 111 and the core shroud 10. And fix it.

Furthermore, lever fixing bolts 114 and 11
The support block 111 is attached and fixed to the riser tube 12 by rotating the rotation lever 4 and closing the grip levers 115 and 115. Next, by connecting the support block 111 to the two-part ring 50 via the connection arm 40, the support block 101 can be securely fixed.

As described above, according to the jet pump clamp device 110 of the second embodiment, it is possible to prevent the stress due to the fluid vibration of the riser pipe 12 with a simple configuration having a smaller number of parts as compared with the first embodiment. it can.

Further, since the gripping levers 115 and 115 for gripping the riser tube 12 are attached to both ends of the support block 111 by lever fixing bolts 114 and 114, respectively, the support block 111 is further firmly fixed to the riser tube 12. can do.

[0094]

As described above, according to the first aspect of the present invention,
According to the jet pump clamp device for reducing the stress due to fluid vibration generated in the welded portion of the riser pipe of the jet pump installed in the reactor pressure vessel,
A two-part ring abutting on the outer periphery of the welded portion between the lower part of the riser pipe and the thermal sleeve connected to the riser pipe; an engaging recess formed in one of the two split rings and engaged with the other in the other part; An opening / closing guide portion having a mating engaging projection and a tightening bolt attached to the opening / closing guide portion for opening and closing a two-piece ring, thereby providing a welded portion between the riser pipe of the jet pump and the thermal sleeve. Can be reliably and quickly prevented by underwater remote control with the jet pump installed. As a result, the radiation exposure dose of the workers can be significantly reduced, the soundness of the reactor can be confirmed, and the operation rate of the nuclear power plant can be improved.

Further, since the engagement recess is formed on one of the two split rings and the engagement recess is formed on the other, the opening and closing of the two split rings can be reliably performed.

According to the second aspect, the opening of the split ring according to the first aspect is formed in the same shape as the outer peripheral surface of the lower part of the riser pipe, so that the lower part of the riser pipe and the thermal sleeve are welded. The two-part ring can be fixed to the outer periphery of the part without any gap, and the stress due to fluid vibration generated at the weld between the riser pipe and the thermal sleeve can be significantly reduced.

According to a third aspect of the present invention, there is provided a jet pump clamp apparatus for reducing stress due to fluid vibration generated at a welded portion of a riser pipe of a jet pump installed in a reactor pressure vessel. By providing an upper plate inserted between the core shroud of the vessel and a pressing member for pressing the upper plate between the riser tube and the core shroud, a welded portion between the lower portion of the riser tube and the thermal sleeve is provided. The stress caused by the fluid vibration generated in the above can be reduced.

According to the fourth aspect, in the jet pump clamp device according to the third aspect, a plurality of long rods each having one end connected to the upper plate by a pin, and a pin connected to the other end of each of the long rods. And a lower plate supported by a baffle plate of a jet pump, and a parallel link mechanism comprising an upper plate, a plurality of long rods, and a lower plate. The clamp device can be reliably and quickly installed.

According to the fifth aspect, in the jet pump clamp device according to the third or fourth aspect, when the parallel link mechanism is closed by the pin connecting the upper plate and the plurality of long rods, the closing is adjusted. By providing the restricting stopper, when the parallel link mechanism is closed, the long rods do not completely adhere to each other, and the opening and closing operation of the parallel link mechanism can be performed smoothly.

According to the sixth aspect, in the jet pump clamp device according to the third or fourth aspect, a hanging ear is attached to the upper plate, and when the hanging ear is lifted, the parallel link mechanism is closed by its own weight while the hanging link is closed. The parallel link mechanism is configured to open when the ear is suspended and the lower plate is seated on the baffle plate.
The same effect can be obtained.

According to a seventh aspect of the present invention, in the jet pump clamp device according to the fourth aspect, at least one support is provided at an intermediate portion in the axial direction of the plurality of long rods, and the plurality of long rods are connected via the support. The rigidity of the long rod can be remarkably improved by being supported by the core shroud of the reactor pressure vessel.

According to the eighth aspect, the jet pump can be firmly fixed by connecting the upper plate and the two-piece ring by the connecting arm.

According to the ninth aspect, a support block inserted between the riser tube and the core shroud of the reactor pressure vessel, and the support block is attached to the support block via a tightening bolt and is supported by tightening the tightening bolt. By providing the pressing wedge for pressing the block between the riser tube and the core shroud, it is possible to prevent stress due to fluid vibration of the riser tube with a simple configuration with a small number of parts.

According to the tenth aspect, in the jet pump clamp device according to the ninth aspect, the support block is provided with a gripping lever for gripping the riser pipe, so that the support block can be more firmly fixed to the riser pipe. it can.

According to the apparatus for handling a jet pump clamp apparatus according to the eleventh aspect, a jet pump clamp apparatus for reducing stress caused by fluid vibration generated at a welded portion of a riser pipe of a jet pump installed in a reactor pressure vessel is handled. A handling device for a jet pump clamp device,
A holding member for holding an open state of a two-part ring that can be brought into contact with the outer periphery of a welded portion between a lower portion of the riser tube and a thermal sleeve connected to the riser tube, and turning the holding member provided on the holding member By providing a swing drive means, a suspension plate attached to the swing drive means, and an extrusion drive means provided on the holding member and extruding a two-piece ring, a jet is formed at a welding portion between the lower portion of the riser pipe and the thermal sleeve. A two-piece ring as a pump clamp device can be easily mounted.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a jet pump clamp device according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a cross-sectional view showing a state when the parallel link mechanism according to the first embodiment is moved.

FIG. 5 is a sectional view showing a two-part ring according to the first embodiment;

FIG. 6 is a side view showing the two-part ring according to the first embodiment.

FIG. 7 is a partially enlarged cross-sectional view showing a two-piece ring according to the first embodiment.

FIG. 8 is a front view showing one embodiment of a handling device of the jet pump clamp device according to the present invention.

FIG. 9 is a side view of FIG. 8;

FIG. 10 is a plan view showing a holding frame of the handling device of FIG. 8;

FIG. 11 is a schematic plan view showing the operation of the handling device of FIG.

FIG. 12 is a schematic diagram for explaining a use state of the jet pump clamp device according to the first embodiment of the present invention in a nuclear reactor.

FIG. 13 is an enlarged side view of a portion C in FIG.

FIG. 14 is a sectional view showing a second embodiment of the jet pump clamp device according to the present invention.

FIG. 15 is a plan view showing a support block according to a second embodiment.

FIG. 16 is a sectional view showing a configuration of a general boiling water reactor.

FIG. 17 is a partially cutaway perspective view showing a conventional jet pump.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 reactor pressure vessel 2 coolant 3 reactor core 4 steam separator 5 steam dryer 6 main steam pipe 7 downcomer section 8 control rod guide pipe 9 control rod drive mechanism 10 core shroud 11 jet pump 12 riser pipe 13 recirculation inlet nozzle Reference Signs List 14 transition piece 15 elbow 16 mixing nozzle 17 inlet throat 18 diffuser 19 measurement pipe 20 riser brace 21 ear 22 groove 23 jet pump beam 24 head bolt 25 riser blanket 26 baffle plate 27 support 28 elbow 29 thermal sleeve 30 parallel link mechanism 31 Upper plate 32 Pin 33 Long rod 34 Pin 35 Lower plate 36 Arc surface part 37 Spring (pressing member) 38 Pin 39 Hanging ear 40 Connecting arm 41 Intermediate support 42 Arc Part 43 flat part 50 two-part ring 51 upper ring 52 lower ring 53 opening and closing guide part 54 engaging concave part 55 engaging convex part 56 fastening bolt 57 flange 58 female screw collar 59 opening and closing block 60 fastening bolt 61 locking bolt 62 upper shaft 63 Upper shaft hole 64 Return member 65 Large diameter hole 66 Screw part 67 Screw hole 68 Screw part 69 Screw hole 70 Screw hole 71 Detachment prevention flange 72 Nut 73 Folding washer 74 Folding member 75 Stopper 76 Circular hole 80 Handling device 81 Holding frame 82 Slewing motor (slewing drive means) 83 Pole 84 Suspension plate 85 Suspension plate 86 Cylinder (extrusion drive means) 87 Notch groove 88 Notch hole 89 Notch hole 90 Moving member 91 Hanging ear 100 Upper grid plate 101 Core support plate 103 Fuel exchanger 104 Pole handling mechanism 10 Paul 106 Hoist 107 wire 108 pole connecting unit 109 the nut runner 110 jet pump clamping device 111 support block 112 clamping bolts 113 pressing wedge 114 lever fixing bolt 115 gripping lever

Claims (11)

[Claims] 1. A jet pump clamp device for reducing stress due to fluid vibration generated at a welded portion of a riser pipe of a jet pump installed in a reactor pressure vessel, wherein the lower part of the riser pipe is connected to the riser pipe. A two-part ring that abuts the outer periphery of the welded portion with the thermal sleeve, and an engagement recess formed on one of the two rings and an engagement projection engaged with the engagement recess on the other side. A jet pump clamp device comprising: an opening / closing guide portion; and a tightening bolt attached to the opening / closing guide portion to open and close the two-piece ring. 2. The jet pump clamp device according to claim 1, wherein the opening of the two-part ring is formed in the same shape as the outer peripheral surface of the lower part of the riser pipe. 3. A jet pump clamp apparatus for reducing stress caused by fluid vibration generated at a welded portion of a riser pipe of a jet pump installed in a reactor pressure vessel, wherein the riser pipe and a reactor core of the reactor pressure vessel are provided. A jet pump clamp apparatus comprising: an upper plate interposed between a shroud; and a pressing member for pressing the upper plate between the riser tube and the core shroud. 4. The jet pump clamp device according to claim 3, wherein a plurality of long rods each having one end connected to the upper plate by a pin, and the other end of each of the long rods being connected to each other by a pin. A lower plate supported by a baffle plate,
A jet pump clamp device, wherein a parallel link mechanism is constituted by the upper plate, a plurality of long rods and a lower plate. 5. The jet pump clamp device according to claim 3, wherein a pin for connecting the upper plate and the plurality of long rods is provided with a stopper for restricting the degree of closing when the parallel link mechanism is closed. A jet pump clamp device, characterized in that: 6. The jet pump clamp device according to claim 3, wherein a hanging ear is attached to the upper plate, and when the hanging ear is lifted, the parallel link mechanism is closed by its own weight, and the hanging ear is hung. A jet pump clamping device, wherein the parallel link mechanism is opened when the lower plate is seated on the baffle plate. 7. The jet pump clamp device according to claim 4, wherein at least one support is provided at an axially intermediate portion of the plurality of long rods, and the plurality of long rods are connected to the reactor pressure vessel via the support. A jet pump clamp device supported by a core shroud. 8. A jet pump clamp apparatus for reducing stress due to fluid vibration generated at a welded portion of a riser pipe of a jet pump installed in a reactor pressure vessel, wherein the lower part of the riser pipe is connected to the riser pipe. A two-part ring that abuts the outer periphery of the welded portion with the thermal sleeve, and an engagement recess formed on one of the two rings and an engagement projection engaged with the engagement recess on the other side. An opening / closing guide portion, a tightening bolt attached to the opening / closing guide portion for opening and closing the two-part ring, an upper plate inserted between the riser tube and a core shroud of the reactor pressure vessel, A pressing member for pressing a plate between the riser tube and the core shroud, and connecting the two-piece ring and the upper plate A jet pump clamp device comprising a connecting arm. 9. A jet pump clamp apparatus for reducing stress caused by fluid vibration generated at a welded portion of a riser pipe of a jet pump installed in a reactor pressure vessel, wherein the riser pipe and a reactor core of the reactor pressure vessel are provided. A support block inserted between the shroud and a pressing wedge which is attached to the support block via a tightening bolt and presses the support block between the riser tube and the core shroud by tightening the tightening bolt; And a jet pump clamp device comprising: 10. The jet pump clamp device according to claim 9, wherein a gripping lever for gripping the riser tube is provided on the support block. 11. A handling apparatus for a jet pump clamp apparatus for handling a jet pump clamp apparatus for reducing stress caused by fluid vibration generated in a weld of a riser pipe of a jet pump installed in a reactor pressure vessel, wherein the riser is provided. A holding member that holds an open state of a two-part ring that can contact an outer periphery of a welded portion between a lower portion of the pipe and a thermal sleeve connected to the riser pipe; and a rotating member provided on the holding member. An apparatus for handling a jet pump clamp device, comprising: a swing drive means; a suspension plate attached to the swing drive means; and an extrusion drive means provided on the holding member and extruding the two-piece ring.