JPH10142393A - Device for fixing cap of piping nozzle in water chamber of vertical steam generator and its installation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out work for fixing a nozzle cap in a short time by using a hooking lock mechanism of a cam-lever type for a device for fixing the nozzle cap to make the hooking lock mechanism hook and lock or release by a single action. SOLUTION: An annular lock groove (d) is formed on the outer- circumferential face of a hold-down ring C. A gasket B is sandwiched between a nozzle cap A and the hold-down ring C to seal a nozzle water-tightly. A fitting bracket 31 of a hooking lock mechanism 30 is fixed on the back or the top of a fitting ring 21. A fitting pin 35 is inserted into a pivot hole of an eccentric cam 39 made at a basic end of an operation lever 37 and also into that of a locking hook 41. A tongue 41a protrudes over a tip of the locking hook 41 and enters the lock groove (d) of the hold-down ring C in a locking position. In order to release the hooking lock mechanism 30, the operation lever 37 is pulled up. Then, the eccentric cam 39 rotates, the compressive force acting on the gasket B decreases, the locking hook 41 rotates and he mechanism 30 is released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for closing a nozzle of a pipe for a heating medium connected to a water chamber of a vertical steam generator of a heat exchanger type. The present invention relates to a device for mounting and fixing a lid for closing a nozzle portion of an indoor coolant pipe.

[0002]

2. Description of the Related Art In a pressurized water reactor plant, a vertical steam generator is used to convert heat of a reactor coolant into steam for driving a turbine. A typical example of this type of steam generator is a heat exchanger type having a tube bundle composed of an inverted U-shaped heat transfer tube, and a water chamber through which a reactor coolant enters and exits is formed at a lower portion. That is, a coolant pipe through which the reactor coolant flows communicates with the water chamber, forming a nozzle at the boundary.When inspecting and repairing the reactor plant, the nozzle is closed with a nozzle lid. That is being done. Referring to FIG. 8, the lower end plate 1 of the steam generator defines a water chamber 3, and a nozzle 1 a to which a coolant pipe 5 is joined forms a nozzle portion 7. A hold-down ring 9 is attached to the inner surface of the water chamber 3 so as to surround the nozzle portion 7, and the nozzle lid 11 is fixed by bolts 13 screwed into screw holes formed in the hold-down ring.
By doing so, the inside of the water chamber 3 can be kept in a dry state while the inside of the coolant pipe 5 is filled with water.

In order to mount such a nozzle lid 11, a foldable or split-assembly type nozzle lid 11 is brought into the water chamber 3 from the manhole 15, and an operator 17 uses a manual tool 19 such as a wrench to 13 had been tightened. However, in the case of tightening with a manual tool by an operator, a tightening torque for achieving a liquid-tight state cannot be obtained in many cases. Was set and retightened.

[0004]

However, since the inner surface of the water chamber 3 may become radioactive due to contact with the reactor coolant flowing in and out of the coolant pipe 5, the inside of the water chamber 3 is exposed to radiation. Levels are high and are generally not favorable for workers. On the other hand, the diameter of the nozzle portion 7 is large, and the nozzle lid must be attached so as not to cause water leakage. Therefore, the number of bolts 13 is inevitably increased. The time required for the attachment work also increases. Therefore, there is a problem that frequent replacement of workers is required to maintain the health of workers in a radiation atmosphere. In addition, remote guide devices such as a hydraulic torque wrench are expensive, and installation of these devices in the water chamber requires the installation of related equipment such as hydraulic piping and a hydraulic pressure generator. Also requires a large amount of work time. Also, nozzle cover 1
Attaching 1 requires a series of operations such as bringing the nozzle lid 11 into the water chamber 3, positioning and setting the nozzle lid 11 on the hold-down ring 9, and screwing the bolt 13. The remote guidance device is
They performed only a small part of these tasks, and had to rely on workers for a significant amount of work. Therefore, there has been a demand for a lid fixing device for a pipe nozzle in a water chamber of a vertical steam generator, which does not require an expensive remote operation device and can perform an installation operation by an operator in an extremely short time. The present invention has been made to meet such needs.

[0005]

According to the present invention which solves the above-mentioned needs, a lid fixing device for a pipe nozzle of a water pipe of a vertical steam generator is provided with a ring surrounding a pipe nozzle of a water chamber of a vertical steam generator. A mounting ring opposed to the mounting seat with the peripheral edge of the nozzle lid interposed therebetween, and a plurality of hook locking mechanisms disposed at intervals in the circumferential direction on the mounting ring, the mounting ring not facing the nozzle lid; A mounting bracket protruding from the rear surface of the mounting bracket and having a long hole, a locking hook having a base end pivotally supported by the mounting pin inserted through the long hole, and pivotally connected to the mounting pin. An operating lever including an eccentric cam portion, a first biasing member fixed to the mounting ring and applying a force in a release direction to the locking hook;
The second locking member is fixed to the mounting ring and cooperates with the operation lever to apply a force to the locking hook in the direction of engagement. Preferably, the mounting ring is circumferentially split and reassembled so as to be convenient to carry through the manhole into the water chamber, and in some cases the component ring is configured to be foldable. Further, in order to hold the locking hook once hooked and locked to the mounting seat, it is preferable to provide a release ring with a release prevention stopper which engages with the locking hook. Further, instead of or in combination with the release prevention stopper, a semicircular ring is further provided with a holding ring which is connected via a hinge and is configured to be freely foldable. May be arranged at intervals in a plurality of circumferential directions, and the operating levers of all the hooking and locking mechanisms may be forcibly and collectively held. Furthermore, in order to reduce the required operating force of the operation lever, an extension rod may be provided detachably at the tip of the operation lever of the hooking and locking mechanism. Further, the mounting device for easily bringing the lid fixing device of the pipe nozzle of the water chamber into the water chamber of the vertical steam generator includes a pulling mechanism including a pulley mounted on a ceiling of the water chamber and a manhole portion of the water chamber. And a work tool that is exchangeably attached to the tip of the manipulator arm.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, the overall structure of the lid fixing device 20 will be described with reference to FIG. Nozzle lid A as described below
Mounting ring 2 placed on the back or top edge
Reference numeral 1 denotes an annular assembly of two ring segments 23 and two ring segments 25, and a carrying handle 27 is attached to each of the ring segments 23, 25 at a substantially central portion. Further, a mounting pin 29 is attached to the peripheral end of each of the ring segments 23 and 25.
Holes and mounting hardware 31 are provided, which are combined together as shown to integrally connect the ring segments 23, 25 as described above. The mounting pin 29
Is planted on the back of the nozzle lid A. The use of the mounting pin 29 fixed to the nozzle lid A in this manner is convenient for positioning the mounting ring 21 at a regular position and assembling the mounting ring 21. On the back surface of the mounting ring 21 that does not contact the nozzle lid A, a plurality of, in the illustrated case, ten
Are mounted at predetermined intervals. The nozzle lid A is composed of divided plates a, b, and c so that it can be brought in from a manhole of a water chamber (not shown). Assembled into a shape. If the above-mentioned mounting pin 29 is provided as an alignment pin and protrudes from a hold-down ring described later and protrudes from the back surface of the nozzle cover A, it is convenient to mount the nozzle cover A. The nozzle lid A
An appropriate number is selected in consideration of the handleability in consideration of the size and weight of the manhole.

FIG. 1 shows a detailed structure of the hook locking mechanism 30. As shown in FIG. An annular mounting seat or hold-down ring C which is fixed by welding or the like around a nozzle portion of a water chamber not shown in FIG. 1 has the same outer shape as the above-mentioned hold-down ring 11, but has an outer peripheral surface. An annular locking groove d is formed. A rubber gasket B is sandwiched between the nozzle lid A and the hold-down ring C to achieve a watertight closure. The gasket B has a relatively thin central portion but a relatively thick peripheral portion as shown in the figure, and is formed in a relatively thick disk shape, thereby facilitating deformation of the peripheral portion due to compression and ensuring water-tight joining. Although the nozzle lid A has sufficient rigidity and strength to withstand the water pressure received through the gasket B, the weight is reduced in consideration of handleability. The mounting bracket 31 of the hooking and locking mechanism 30 is fixed to the back or upper surface of the mounting ring 21 that does not contact the nozzle lid A. Mounting bracket 31
Is formed with an elongated hole 33 extending in the up-down direction (in the figure, the same applies hereinafter), through which a mounting pin 35 is inserted. The mounting pin 35 is inserted through the pivot shaft hole of the eccentric cam 39 formed at the base end of the operation lever 37, and is further inserted through the pivot shaft hole of the locking hook 41. A tongue portion 41a is formed at the tip of the locking hook 41 so as to protrude, and enters the locking groove d of the hold-down ring C at a locking position as shown in the figure. Further, a notch 43 is formed in an intermediate portion of the locking hook 41, and a stopper pin 45 on the mounting ring 21 side is formed.
Engages.

[0008] Nozzle lid A and hold down ring C
Has a disc-like or annular shape as understood from FIG. 2, the center of which is not shown is on the right side in FIG. 1, but the surface of the locking hook 41 located on the center side, that is, A first biasing member or pushing mechanism 50 faces the inner surface 41b.
Is provided. The pushing mechanism 50 includes a compression coil spring 51, a casing 53 having a hole for receiving the compression spring 51, and a projection extending from a distal end of the casing 53.
1 comprises a hook pushing pin 55 pushed leftward. The elastic restoring force of the coil spring 51 is applied to the inner surface 4 of the locking hook 41 via the hook pushing pin 55.
1b, the locking hook 41 is about to pivot in the direction of arrow m, ie, in the release direction. On the other hand, locking hook 4
A second biasing member, that is, a push-in mechanism 60 is provided opposite to the push-out mechanism 50 with respect to 1. Closet mechanism 60
Are a pivot pin 61, a pivot contact member 63 supported by the pivot pin 61, a compression coil spring 65 which contacts the back surface of the pivot contact member 63 and pivots it counterclockwise and a spring casing 67. It is composed of The elastic restoring force of the coil spring 65 is applied to the locking hook 41 via the pivot contact member 63.
Is transmitted to the outer side surface 41c. The spring constants of the coil springs 51 and 65 are determined so that the counterclockwise rotation moment transmitted to the locking hook 41 by the coil spring 65 is greater than the clockwise rotation moment by the coil spring 51. In this state, the engagement relationship between the locking hook 41 and the hold-down ring C is maintained.

In order to operate the hooking and locking mechanism 30 as described above, the eccentric cam 39 is rotated around the mounting pin 35 by grasping the operation lever 37, but is extended to reduce the necessary force at that time. A rod 49 is mounted on the tip of the operation lever 37.
This state is shown in FIG. Of course, such an extension rod 49 must be rotated in a narrow water chamber, and thus has a length that does not hinder the rotation operation. on the other hand,
As described above, the locking hook 41 is connected to the hold down ring C
In order to perform the other water chamber work while holding the hook locking mechanism 30 in the locked state for a long time, the operation levers 37 are all held together by the holding ring 70 as shown in FIGS. Is preferable because of high reliability. The holding ring 70 has a semicircular ring 73 foldably connected by a hinge 71, and a holding pipe 75 provided on the lower surface thereof in correspondence with the hooking and locking mechanism 30. The holding pipe 75 can be moved in the radial direction, is moved outward in the radial direction, is inserted into the horizontally held operation lever 37, and is fixed at that position, that is, in the state shown in the drawing. In this way, even if the engagement between the stopper pin 45 and the locking hook 41 is released for some reason, the operation lever 37 is maintained at a normal position, and the nozzle cover A is securely fixed.
When the holding ring 70 is brought into the water chamber through the manhole, it is bent at the hinge 71 to reduce the size. However, depending on the geometrical relationship between the manhole and the holding ring 70, instead of the hinge 71, the mounting ring 21 is used. A simple connecting method may be adopted to increase the number of divisions.

In order to release the hooking and locking mechanism 30 mounted as shown in FIG.
Cause in the direction of. With this operation, the eccentric cam 39 becomes
The gasket B rotates around the mounting pin 35, and as the cam radius decreases, the compressive force acting on the gasket B decreases, and the amount of deformation of the gasket B decreases. Therefore, mounting ring 2
1 moves away from the hold down ring C, the stopper pin 45 also moves in the direction of arrow q,
Allows rotation in the direction. However, in this state, the state of FIG. Finally, the outer peripheral surface 39a of the eccentric cam 39 is
3 and pivots the pivot contact member 63 clockwise (arrow r) against the coil spring 65. Then, the pivot contact member 63 is released from the locking hook 41, and the locking hook 41 moves in the direction of arrow s and rotates clockwise by the action of the pushing mechanism 50. This state is shown in FIG.

FIG. 5 shows a state in which the operating lever 37 of the hooking and locking mechanism 30 is raised as described above, and is released and disengaged, in other words, a state where it is about to be engaged. Since the pivot contact member 63 is separated from the locking hook 41, the force of the coil spring 65 is not transmitted to the locking hook 41, and only the force of the coil spring 51 of the pushing mechanism 50 acts. Leaning outward. Although the gap between the nozzle lid A and the gasket B is exaggerated, the nozzle lid A is moved in the direction of the arrow t to rest on the gasket B. In order to insert and lock the tongue 41a of the locking hook 41, which has been separated here, into the circumferential groove d of the hold-down ring C, the operation lever 37 is rotated in the direction of arrow u. The pivot contact member 63 is pushed in the direction of arrow v by the coil spring 65, and finally the outer surface 41 of the locking hook 41.
c, and overcomes the push-out mechanism 50 to stop the locking hook 41.
Is rotated in the direction of arrow x to insert the tongue 41a into the circumferential groove d. As the cam radius of the eccentric cam 39 increases, the mounting ring 21 is pressed downward, compressing the peripheral edge of the gasket B, and moving the stopper pin 45 in the direction of arrow y to finally reach the state shown in FIG.

Next, a description will be given of a device for bringing the nozzle lid A, the gasket B and the lid fixing device 20 as described above into the water chamber 3 of the steam generator and mounting the same. Referring to FIG. 6, the pulling mechanism 80 includes a pulley 81 fixed to the tube plate at the ceiling of the water chamber 3, an arm guide member 83 fixed around the manhole 15 of the lower end plate 1, and an arm guide member 83. The attached electric hoist 85, a wire 8 extending from the electric hoist 85, wound around the pulley 81, and provided with a gripping tool at the tip thereof
Seven. The manipulator arm 90 is attached to an arm guide member 83, and has a tongue type hand 91 at the end.
Work tools such as are attached. Then, in order to carry in the gasket B, the substantially circular gasket B is folded outside the water chamber 3, one end of the gasket B is gripped by a gripping tool at the tip of a wire 87, and the other end is tongue-type hand 91 of the manipulator 90.
Grab it with Then, the electric hoist 83 and the manipulator 90
Is carried through the manhole 15 in conjunction with. The nozzle cover A is divided into divided plates a, b, and c, and the lid fixing device 20 is divided into ring segments 23 and 25 to which the hooking / locking mechanism 30 is attached. Carry in the room. At this time, most of the weight of the transferred object is shared by the wire 87, and the manipulator arm 90 mainly performs a guiding and positioning operation. At that time, it is convenient to use the alignment 14 attached to the hold-down ring C. These tasks are performed remotely.
When the use of the nozzle cover A is finished and the nozzle cover A, the gasket B, and the cover fixing device 20 are carried out of the water chamber 3 to the outside of the lower end plate 1, the above-described operation procedure may be performed retroactively.

In order to operate the operation lever 37 of the hooking / locking mechanism 30 by using the manipulator arm 90, a remote air hammer 93 is attached to the tip as a working tool as shown in FIG. 97, and the contact metal 99 is pressed against the operation lever 37. Operation lever 3
To rotate or pull up 7 in the opposite direction, a force may be applied in the opposite direction in a similar manner. Note that the support portion 97 may be attached to the upper surface of the nozzle lid A in advance.

[0014]

As described above, according to the present invention,
The cam-lever type hook-and-lock mechanism is used for the nozzle lid fixing device, so that the hook-and-lock mechanism can be brought into the hook-and-lock state or released by one rotation, and the water chamber can be closed in a very short time. The work of fixing the nozzle lid can be performed. or,
According to the present invention, by using the holding ring having the holding pipe, the hooking locking mechanism can be stably held in the locked state for a long time. Further, according to the present invention, by using the lifting mechanism having the electric hoist and the manipulator arm together, the nozzle lid fixing device and the like can be easily carried into and out of the water chamber of the steam generator.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a main part of an embodiment of a hook locking mechanism according to the present invention.

FIG. 2 is an overall perspective view showing an embodiment of a lid fixing device according to the present invention.

FIG. 3 is a top view showing a state where a holding ring is attached to the lid fixing device of FIG. 2;

FIG. 4 is a sectional view taken along line IV-IV in FIG. 3;

FIG. 5 is an explanatory diagram of an operation of the hook locking mechanism.

FIG. 6 is an overall view showing a state in which the lid fixing device and the like are brought into a water chamber and attached.

FIG. 7 is an explanatory diagram showing a state in which an operation lever of the hooking locking mechanism is operated using a manipulator.

FIG. 8 is an explanatory view showing a conventional nozzle lid attachment state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower end plate 3 Water chamber 7 Nozzle part 14 Alignment pin 15 Manhole 20 Lid fixing device 21 Mounting ring 23, 25 Ring segment 27 Handle 29 Mounting pin 31 Mounting bracket 30 Hook locking mechanism 31 Mounting bracket 33 Long hole 35 Mounting pin 37 Operation Lever 39 Eccentric cam 39a Outer peripheral surface 41 Locking hook 41a Tongue 41b Inner surface 41c Outer surface 43 Notch 45 Stopper pin 49 Extension rod 50 Pushing mechanism 51 Coil spring 53 Casing 55 Hook pushing pin 60 Pushing mechanism 61 Pivot pin 63 pivot Moving contact member 65 Coil spring 67 Spring casing 70 Holding ring 71 Hinge 73 Semicircular ring 75 Holding pipe 80 Pulling mechanism 81 Pulley 83 Arm guide member 85 Electric hoist 87 Wire 90 Manipulator arm 9 Reference Signs List 1 tong type hand 93 remote air hammer 95 reaction force receiver 97 support part 99 money A nozzle cover B gasket C hold down ring

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yukihide Shimazu 1-1-1, Wadazakicho, Hyogo-ku, Kobe-shi, Hyogo Nuclear Service Engineering Co., Ltd. (72) Inventor Shoji Terawaki Wadazaki, Hyogo-ku, Kobe-shi 1-1-1 Machi Nuclear Service Engineering Co., Ltd. (72) Inventor Hidekazu Inui 5-1-1-16 Komatsu-dori, Hyogo-ku, Kobe-shi, Hyogo Prefecture Shinryo High-Tech Co., Ltd.

Claims (6)

[Claims] 1. An annular mounting seat surrounding a pipe nozzle in a water chamber, a mounting ring opposed to the annular mounting seat with a peripheral edge of the nozzle lid interposed therebetween, and a plurality of hooking and locking mechanisms arranged at circumferentially spaced intervals on the mounting ring. A mounting bracket protruding from the back of the mounting ring not facing the nozzle lid and having a long hole, and a locking hook having a base end pivotally supported by a mounting pin inserted through the long hole. An operating lever including an eccentric cam portion pivotally connected to the mounting pin; a first biasing member fixed to the mounting ring for applying a force to the locking hook in a releasing direction; And a second biasing member that cooperates with the operating lever to apply a force to the locking hook in an engaging direction, and the hooking locking mechanism is configured to comprise the water chamber of the vertical steam generator. Piping nozzle Lid fixing device. 2. The fixing device for a pipe nozzle of a vertical steam generator according to claim 1, wherein the mounting ring is configured to be freely divided and reassembled in a circumferential direction. 3. The pipe nozzle of a vertical steam generator according to claim 1, wherein said mounting ring is provided with a release prevention stopper which engages with said locking hook. Lid fixing device. 4. The piping in a water chamber of a vertical steam generator according to claim 1, wherein an extension rod is detachably provided at a tip of the operation lever of the hooking locking mechanism. Nozzle lid fixing device. 5. A plurality of holding pipes for individually receiving tips of the operation levers of the plurality of hooking and locking mechanisms are arranged at intervals in a plurality of circumferential directions, and semicircular rings are connected via hinges. The fixing device for a pipe nozzle of a vertical steam generator according to claim 1 or 2, further comprising a holding ring configured to be freely foldable. 6. A pull-up mechanism including a pulley attached to a ceiling portion of the water chamber, a manipulator arm fixed to a manhole portion of the water chamber, and a work tool exchangeably attached to a tip of the manipulator arm. A mounting device for a lid fixing device for a pipe nozzle in a water chamber of a vertical steam generator according to claim 1.