JP2006284189A - Device and method of polishing internal pump nozzle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable certain removal of activated crud adhering to the upper face of an internal pump nozzle. <P>SOLUTION: A nozzle upper plug 17 is disposed on the upper part of a nozzle 5 of an internal pump to cover the upper face 7a of the nozzle 7, the polishing device 20 is installed from the lower part of a motor casing 7, a polishing head section 21 is moved into the nozzle upper plug 17 in a contraction state, then the polishing head section 21 is extended horizontally, and a sandpaper 21c is pressed onto the nozzle upper face 5a and rotated circumferentially, thereby polishing and removing the crud adhering to the nozzle upper face 7a with the sandpaper 21c. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is an apparatus for removing clad adhering to the upper surface of an internal pump mounting nozzle (hereinafter also simply referred to as an internal pump nozzle or nozzle) used for coolant circulation in an improved boiling water reactor. And a method.

  The improved boiling water reactor is equipped with an internal pump in the reactor pressure vessel and a pump for circulating the coolant (reactor water) in the reactor pressure vessel to the reactor core. As an example of a cleaning apparatus and a cleaning method for removing the clad adhering to the internal pump and the nozzle, a cleaning apparatus is installed in the motor casing below the reactor pressure vessel as described in Patent Document 1, and a brush is used. There are an apparatus and a cleaning method for cleaning by moving up and down or rotating.

Japanese Patent No. 2896443

  A gasket is fixed to the lower end of the boss portion of the diffuser of the internal pump, and the gasket comes into contact with the upper surface of the nozzle to cause leakage of cooling water in the radial direction of the nozzle between the diffuser and the upper surface of the nozzle. To prevent that. However, fine clad particles or the like are deposited or firmly adhered to the upper surface of the nozzle to which the diffuser is attached. When the diffuser is attached to the upper surface of the nozzle, the gasket on the lower surface of the diffuser boss and the upper surface (sitting of the nozzle) If clad particles or the like remain between the surfaces, the sealing function of the seating surface may be hindered.

  In the conventional method, it is only possible to clean the member on the same axis as the motor casing of the internal pump, it is difficult to remove the clad stuck to the upper surface of the nozzle arranged perpendicular to the axis, and ensuring the sealing function of the seating surface Not considered. In addition, the cladding removal operation by the conventional method is performed in water in which the nuclear reactor is filled with reactor water. However, if polishing is performed with the upper part of the nozzle open, the removed cladding is in the reactor water. Since it diffuses, when the waste water is treated from the lower part of the motor casing, a large amount of radioactive clad contained in the reactor water is brought into the motor casing, which may increase the cleaning work in the motor casing.

  Therefore, the object of the present invention is to ensure the sealing function of the diffuser seating surface by polishing the upper surface of the nozzle of the internal pump.

  An apparatus for achieving the object of the present invention includes an expansion / contraction mechanism that can expand and contract between a width that can pass through the inside of a nozzle to which a diffuser of an internal pump is attached, and a width that overlaps the upper surface of the nozzle, and the expansion / contraction mechanism A polishing material mounted at a position facing the upper surface of the nozzle, an operation means for expanding and contracting the expansion / contraction mechanism, a rotation means for rotating the expansion / contraction mechanism, a lifting / lowering means for moving the expansion / contraction mechanism up and down, and the lifting / lowering means And an internal pump nozzle polishing device comprising a base plate mounted with the same, and a method comprising an internal pump nozzle provided in a reactor pressure vessel and a nozzle provided in the reactor pressure vessel. Removing a component equipped in the pump casing of the pump and a component equipped in the nozzle; and the internal Attaching a plug to the nozzle after removing the components of the pump so that the upper surface of the nozzle is included inside, and sealing between the inside of the reactor pressure vessel and the inside of the nozzle; and the sealing An internal pump nozzle polishing method comprising: a step of turning the inside of the pump casing after being stopped into a gas atmosphere; and a step of polishing the upper surface of the nozzle in the gas atmosphere.

  According to the present invention, since the upper surface of the nozzle of the internal pump already installed in the reactor pressure vessel can be polished, the sealing function of the seating surface of the diffuser of the internal pump can be reliably ensured.

In the present invention, the upper surface 7a of the nozzle 7 of the internal pump 2 is polished with sandpaper 21c, which is a polishing material, so that the clad that impedes the sealing function between the upper surface 7a of the nozzle 7 and the diffuser 6 is removed. The sealing function of the seating surface of the diffuser 6 of the null pump 2 is ensured.

  The first embodiment of the present invention will be described below. The internal pump 2 used for the coolant circulation in the improved boiling water reactor is installed at the bottom (lower mirror) of the reactor pressure vessel 1 as shown in FIG. FIG. 1 shows a part of a reactor pressure vessel 1 and a cross section of an internal pump 2. In FIG. 1, the internal pump 2 includes a pump unit 3 and a motor unit 4. By driving the pump unit 3 with the motor unit 4, the reactor water inside the reactor pressure vessel 1 is circulated to the core.

  The pump unit 3 includes an impeller 5 and a diffuser 6 that surrounds the periphery of the impeller 5, and the impeller 5 is connected to the motor unit 4 via a shaft 5b. The diffuser 6 includes a diffuser boss portion 6 a that extends downstream from the impeller 5. The upper surface 7 a of the nozzle 7 of the internal pump 2 provided in the lower mirror portion of the reactor pressure vessel 1 (the seat of the diffuser boss portion 6 a is seated). The lower end of the diffuser boss portion 6a is hooked on the stretch tube 8 so as not to be disengaged upward. The stretch tube 8 is fixed to the pump casing 9 by a stretch tube nut 12 from the lower part in the pump casing 9. A secondary seal 13 is provided below the stretch tube nut 12.

  The motor unit 4 is composed of a rotor 10 and a stator 11 of a motor built in the pump casing 9, a motor cover 14 covering them, and the like. Housed inside. The motor cover 14 is attached so as to close the lower end opening of the pump casing 9, and a plurality of stud bolts 15 provided at the lower end of the pump casing 9 and nuts 16 screwed into the stud bolts 15 are used to pump the pump casing 9. 9 is fastened and fixed.

  In such an internal pump 2, when the shaft 5b is rotationally driven by the motor unit 4, the impeller 5 fixed to the shaft 5b also rotates to move the reactor water in the reactor pressure vessel 1 downward from above in FIG. It can be sent out through the diffuser 6 to the core.

  An internal pump nozzle polishing apparatus (hereinafter also simply referred to as a polishing apparatus) 20 according to the first embodiment of the present invention is configured in an internal pump 2 such as a motor section 4 and a pump section 3 from the pump casing 9 and the nozzle 7. The parts are removed and once removed from the reactor pressure vessel 1, and then placed in the pump casing 9 or the nozzle 7 after the removal.

  FIG. 6 shows the internal pump nozzle polishing apparatus 20. The polishing apparatus 20 has the following configuration. That is, in FIG. 6, the polishing apparatus 20 includes a horizontal disk-shaped flange 24 as a plate for closing the lower end of the pump casing 9.

  The flange 24 is provided with the following lifting means. That is, the lower end of the rod-shaped guide 26 is fixed vertically to the flange 24. Similarly, a screw rod threaded on the outer periphery is arranged vertically as a lifting screw 28 on the flange 24. The lower part of the lifting screw 28 is rotatably mounted on the flange 24 via a bearing, and the lower end of the lifting screw 28 penetrates the flange 24 downward. A lifting handle 25 a is fixed to the lower end of the lifting screw 28.

  The upper end of the guide 26 is fixed to the drainage receptacle 27, and the upper end of the lifting screw 28 is rotatably installed on the drainage receptacle 27 via a bearing. A guide bush 26a is provided on the guide 26 so as to freely move up and down. A screw nut 28a is screwed into the screw portion of the elevating screw 28. A horizontal plate is fixed to the guide bush 26a and the screw nut 28a to form a connector 22d that connects the two.

  The drain receiver 27 is used to receive the liquid when the upper surface of the nozzle 7 and the inner surface of the nozzle 7 are washed with the liquid. The drainage receiver 27 has a shape obtained by removing a horizontal disk except the lower surface and the outer peripheral portion, and an elastic seal ring 27b protrudes slightly outward from the outer peripheral portion around the entire outer peripheral portion. Is provided.

  An upper end of the pipe is connected to the drain receiver 27 as a drain drain pipe 27a in a vertical posture. A lower portion of the drainage drain pipe 27a penetrates the flange 24 downward, and a connector is provided as a fitting for connection with a hose at a lower end of the drainage drain pipe 27a. A through hole larger than the outer shape of the drainage drain pipe 27b is provided in the flange so that the vertical movement of the drainage drain pipe 27b is allowed in the penetration part, and the drainage drain pipe 27b passes through the flange 24 through the through hole. ing.

  In the center of the drain receiver 27, the connector 22d, and the flange 24, a rotating means passes vertically. The rotating means has the following configuration. That is, the cylindrical hollow rod 22 having a hollow structure passes through the drain receiver 27, the connector 22d, and the center of the flange 24 vertically. The hollow rod 22 is freely movable up and down with respect to the drainage receptacle 27, the connector 22 d and the flange 24. In particular, between the drain receiver 27 and the hollow rod 22, the minimum gap required when the hollow rod 22 moves in the vertical direction between the hollow rod 22 so that the hollow rod 22 does not shake greatly in the horizontal direction. A drain bearing 27 is provided with a slide bearing 22e that supports the horizontal direction of the hollow rod 22 while maintaining the above.

  A rotary handle 22 a is fixed to the lower portion of the hollow rod 22. Further, a stopper 22c is fixed to a portion of the hollow rod 22 between the connector 22d and the drain receiver 27. The stopper 22c has an outer shape that does not pass through the through hole through which the hollow rod 22 passes through the connector 22d.

  An operating rod 23 is inserted into the hollow cavity of the hollow rod 22 as operating means, and the upper and lower ends of the operating rod 23 protrude outward from the upper and lower ends of the hollow rod 22. The operation means has the following configuration. That is, a hollow rod is used as the operating rod 23 of the operating means. A screw is partially machined on the outer peripheral portion of the operation rod 23 and is screwed with a screw machined in advance inside the hollow rod 22.

  A screw is also machined at a portion of the operation rod 23 protruding downward from the hollow rod 22, and a lock nut 22 b is screwed into the screw. Similarly, a head opening / closing handle 23 a is fixed to the lower end of the operation rod 23. The upper end of the operating rod 23 protruding upward from the hollow rod 22 has a flange portion protruding outward in the horizontal direction.

  The upper end of the operation rod 23 is connected to a polishing head portion 21 as an expansion / contraction mechanism that expands and contracts so that the horizontal width is reduced and expanded.

  The configuration of the polishing head unit 21 is as follows. That is, the two lower arms 21b are pivotally mounted on the upper portion of the hollow rod 22 in a V-shaped arrangement as shown in FIG. Similarly, the upper ends of the two upper arms 21a are pivotally attached to each other so as to be vertically rotatable by long pins 21e in an inverted V shape. The upper end of the upper arm 21a and the lower end of the lower arm 21b are pivotally attached by pins so as to be rotatable up and down. The length of the upper arm 21a is longer than the length of the lower arm 21b. As shown in FIG. 2, even if each lower arm 21b rotates in a horizontal state, each upper arm 21a is still in an inverted V shape. It is made to exhibit a bending state.

  As shown in FIG. 4, there are two such combinations of upper and lower arms, and the two sets are connected by a long pin 21e. Furthermore, the two sets of lower arms 21b have plates that connect the lower arms 21b facing each other between the two sets.

  As described above, the polishing head unit 21 includes a substantially rhombic link mechanism including each upper arm and each lower arm as link members, and the horizontal width of the link mechanism passes through the inside of the nozzle 7 by the movement of the link mechanism. It is a mechanism that can expand and contract to a width that can be overlapped with the upper surface 7a of the nozzle 7 in the vertical direction.

  A collar 21f is attached to the outer circumference of the long pin 21e. A hollow rod is joined vertically as an auxiliary rod 21h to the collar 21f, and the auxiliary rod 21h is extended downward. The extended lower end of the auxiliary rod 21h is processed into a shape that covers the flange 21i formed on the upper end of the operating rod 23 from above, as shown in FIG.

Such a polishing head portion 21 is connected to the operating rod 23 of the operating means as follows. That is, the flange 21i of the operating rod 23 is placed inside the extended lower end of the auxiliary rod 21h, and a donut-shaped plate is applied as a lid 21g from the lower side of the flange 21i to the lower end of the auxiliary rod 21h. The lid 21g is fixed to the lower end of the auxiliary rod 21h with a bolt 21j. If it does in this way, the upper end of the operation rod 23 will be connected with the auxiliary rod 21h so that it may not come off in the up-down direction, and the operation rod 23 can rotate with respect to the auxiliary rod 21h.

  Sandpaper is affixed to the lower surface of the plate fixed to the lower arm 21b of the polishing head unit 21 as a polishing material. As the polishing material, an abrasive other than sandpaper may be used.

  A camera 33 is installed in the collar 21f of the polishing head unit 21, and a power supply line and various signal lines of the camera 33 are collected in a single camera cable 33a. The camera cable 33a is passed through the inside of the auxiliary rod 21h from the hole formed in the auxiliary rod 21h, and is passed through the inside of the operating rod 23. The camera cable 33a is drawn out from the lower end of the operating rod 23 and installed outside the polishing apparatus 20. Connected to the device. Therefore, the image captured by the camera 33 can be visually recognized by the image display device.

  Such a polishing apparatus 20 is installed and used in the pump casing 9 of the internal pump as follows. That is, first, in order to insert and install the polishing apparatus 20 in the pump casing 9 of the internal pump, the components of the internal pump are disassembled from the pump casing 9 and the nozzle 7 and removed. The removal method is described in, for example, Japanese Patent Publication No. 7-18947.

  The disassembling operation of the internal pump 2 is usually performed with the reactor pressure vessel 1 filled with water. Therefore, after removing the impeller 5 and the shaft 5b, a cap is applied to the upper end of the boss 6a of the diffuser 6 to prevent the reactor water in the reactor pressure vessel 1 from entering the boss 6a or the nozzle 7. Thereafter, the water in the pump casing 9 is drained and the motor unit 4, the secondary seal 13 and the stretch tube nut 12 are removed downward, and the lower closing flange 31 is attached to the lower end of the pump casing 9. A drainage facility 29 and a water supply facility 30 are installed on the lower closing flange 31 so as to communicate with the inside of the pump casing 9.

  Next, water is supplied into the pump casing 9 until the water supply facility 30 is full, and then the cap is removed from the boss 6a of the diffuser 6 so that the reactor pressure vessel 1 and the pump casing 9 communicate with each other. Thereafter, the diffuser 6 and the stretch tube 8 are pulled upward. After this process, the components of the internal pump 2 are removed from the reactor pressure vessel 1 from the pump casing 9 and the nozzle 7.

  After this removal, the nozzle upper plug 17 is suspended from the upper part of the reactor pressure vessel 1 to the nozzle 7 part. As shown in FIGS. 2 and 5, the nozzle upper plug 17 has a hollow cylindrical hollow structure with the upper part closed, and a seal ring 18 is installed as a seal member on the lower end surface 17a. The seal ring 18 is used for sealing between the nozzle taper portion 7 b of the nozzle 7. The seal ring 18 is made of an elastic material made of, for example, nitrile rubber. A grip portion 19 similar to the impeller grip portion 5a provided at the top of the impeller 5 is installed on the upper portion of the nozzle upper plug 17 so that the nozzle upper plug 17 can be handled by a dedicated handling device for the impeller 5. Keep it.

  When the upper part of the nozzle 7 is sealed by the nozzle upper plug 17, the pump casing 9 and the reactor are fully filled with the lower closing flange 31 attached to the lower opening of the pump casing 9 as shown in FIG. Is maintained. After the nozzle upper plug 17 is seated on the nozzle taper portion 7b by the above-described method, the reactor water in the pump casing 9 is drained by the drainage equipment 29 installed on the lower closing flange 31 below the pump casing 9.

  Next, the nut that fixes the lower closing flange 31 to the pump casing 9 is removed, and the lower closing flange 31 is removed from the pump casing 9. Thereafter, the polishing device 20 is attached to the pump casing 9. The polishing device 20 is attached to the pump casing 9 by inserting a polishing head, lifting means, drainage receiver, hollow rod, and head opening / closing rod into the pump casing 9, and fixing the flange 24 to the lower end of the pump casing 9 with bolts and nuts. To achieve. As the bolt, a stud bolt embedded in the lower end of the pump casing 9 is used, and the stud bolt is passed through a bolt through hole formed in the flange 24 and tightened with a nut.

  Thus, in the state where the polishing apparatus 20 is attached to the pump casing 9, the central axis of the motor casing coincides with the central axis of the hollow rod 22, as shown in FIG. By contacting the inner surface of the cylindrical pump casing 9, the sealing function between the drain receiver and the inner surface of the pump casing 9 can be maintained and maintained. After the polishing device 20 is attached to the pump casing 9, the hose connected to the drainage equipment 29 is connected to the drainage drain pipe 27a.

  In this state, when the lifting handle 25a is rotated to rotate the lifting screw 28, the screw nut 28a is screwed upward, and the guide bush 26a is raised along the guide 26 accordingly. Therefore, the connecting tool 22d fixed to the screw nut 28a and the guide bush 26a is also raised, and the stopper 22c is hooked on the connecting tool 22d. When the connecting tool 22d is raised, the connecting tool 22d is further raised by hooking the stopper 22c, so that the hollow rod 22 integrated with the stopper 22c is raised, and finally the polishing head portion 21 is moved from the upper surface 7a of the nozzle 7. Is also located upward and is contained within the nozzle upper plug 17.

  Thereafter, the lock nut 22b is loosened to release the fixed relationship between the hollow rod 22 and the operating rod 23 by the lock nut 22b. Thereafter, the head opening / closing handle 23a is rotated, and the operating rod 23 is lowered by screwing downward using the screwing relationship between the operating rod 23 and the hollow rod 22. In this manner, the polishing head portion 21 whose horizontal width has been reduced as shown in FIG. 6 expands in the horizontal direction as shown in FIG. This expansion operation is performed until the lower arm 21b becomes horizontal, and when the level is achieved, the rotation of the head opening / closing handle 23a is stopped. Whether or not the level has been achieved is determined by counting the number of rotations of the head opening / closing handle 23a, grasping the count value that becomes horizontal in advance, and achieving the level when the grasped coefficient value is reached. You can consider it. Alternatively, the image of the camera 33 may be checked for confirmation.

  Thus, after stopping the rotation of the head opening / closing handle 23a, the lock nut 22b is tightened to integrate the operation rod 23 on the hollow rod 22 side to prevent relative rotation of both rods. After that, the elevating handle 25a is rotated in the direction opposite to the direction of the previous rotation, and the connecting tool 22d is lowered. The polishing head portion 21 comes into contact with the upper surface 7a of the nozzle 7 by the lowering of the connecting tool 22d, and the sandpaper 21c is applied to the upper surface 7a of the nozzle 7. When the connecting tool 22 d is further lowered, the weight of the hollow rod 22 and the operating rod 23 acts as a force for strongly bringing the sandpaper 21 c into contact with the upper surface 7 a of the nozzle 7 through the polishing head portion 21. In this state, as shown in FIG. 2, the stopper 22c is in a state of floating from the connector 22d. In this way, the weights of the hollow rod 22 and the operating rod 23 are transferred from the connector 22d to the upper surface 7a of the nozzle 7.

  Thereafter, when the rotary handle 22a is rotated to rotate the hollow rod 22, the polishing head portion 21 provided on the hollow rod 22 also rotates horizontally, and the sandpaper 21c is placed on the upper surface 7a of the nozzle 7 so that the polishing head portion 21 The upper surface 7a of the nozzle 7 is polished while adding not only its own weight but also the weight of the hollow rod 22 and the operating rod 23, and the deposits such as the clad existing on the upper surface 7a of the nozzle 7 are polished, and a strong pressure exceeding the own weight of the head portion 21. Polish while applying.

  The state of the polishing work and the state of the polishing result are captured by the camera 33 and visually confirmed by the image display device to confirm the work result.

  In the polishing operation, not only the weight of the polishing head 21 but also the weight of the hollow rod 22 and the operation rod 23 are added to press the sandpaper 21c against the upper surface 7a of the nozzle 7. An annular polishing mark centered at 22 is formed, and when the annular gasket attached to the diffuser 6 is pressed against the annular polishing mark, the formation of a radial leakage flow path in the annular shape of the polishing mark is ensured. This is effective for ensuring a sealing function at the assembly portion of the diffuser 6 and the nozzle 7.

  Further, if the rotary handle 22a installed at the lower portion of the hollow rod 22 is rotated while being pulled downward, the sandpaper 21c is further strongly pressed against the upper surface 7a of the nozzle, and the removal of the clad and the annular polishing mark Generation can be ensured.

  In addition, since the pump casing 9, the nozzle 7, and the nozzle upper plug 17 are in an environment in which they are replaced with gas, the polishing work is performed in the air closed by the nozzle upper plug 17, the flange 24, and the drain receiver 27. As a result, the polished clad floats and diffuses in water, and the spread of contamination by the clad can be suppressed.

After the upper surface of the nozzle 7 is polished in the air, the elevating handle 25a is rotated to raise the connecting tool 22d, and the connecting tool 22 receives the stopper 22c. Thereafter, the lock nut 22b is loosened and the head opening / closing handle 23a is rotated in the reverse direction to reduce the horizontal width of the polishing head portion 21 from the state of FIG. 2 to the state of FIG. Thereafter, the lifting handle 25 a is rotated in the reverse direction to lower the connecting tool 22 d to lower the polishing head portion 21, the hollow rod 22, and the operating rod 23 to a position below the nozzle upper plug 17. Thereafter, the hose of the drainage equipment 29 is removed from the drainage drain pipe 27a. Thereafter, the nut that has fixed the flange 24 to the lower end of the pump casing 9 is loosened, and the entire polishing device 20 together with the flange 24 is pulled out of the pump casing 9 and removed.

  Thereafter, the lower closing flange 31 is attached to the lower end of the pump casing 9 again to seal the lower end, and water is supplied from the water supply facility 30 into the pump casing 9. The water supply from the water supply facility 30 fills the pump casing 9 and the nozzle upper plug 17 with water. Since air is trapped inside the nozzle upper plug 17 when water is supplied, a check valve (not shown) is installed above the nozzle upper plug 17 so that the internal air can be discharged into the reactor pressure vessel 1. It is said. When the pump casing 9 and the nozzle upper plug 17 are filled with water, the nozzle upper plug 17 is removed from the nozzle 9. Removal of the nozzle upper plug 17 is carried out by gripping and handling the grip portion 19 fixed to the upper surface of the nozzle upper plug 17 with the dedicated handling device of the impeller 5 in the same manner as in the mounting.

  In this way, the pump casing 9 and the nozzle 7 are again emptied and then filled with water, and then the components of the internal pump 2 and the nozzle 7 are reversed in the reverse order of disassembly. To install.

  In this embodiment, the lifting and lowering means, the operating means, and the rotating means of the polishing apparatus are driven by manually rotating various handles. However, the driving may be performed using an air motor or an electric motor.

  In the second embodiment of the present invention, the function of polishing the inner surface of the nozzle is added to the first embodiment described above. In the second embodiment, the following configuration is added to the configuration of the first embodiment, and the other configurations are the same as those of the first embodiment, so the added configuration will be described below. Description of other configurations is omitted.

  The structure added to the contents of the first embodiment is as shown in FIG. 3, that is, the brush 32 is moved to the outer peripheral surface of the hollow rod 22 of the polishing apparatus and the inner peripheral surface of the nozzle 7 as shown in FIG. Fix to length.

  With such a configuration, as shown in FIG. 3, when the upper surface 7a of the nozzle 7 is polished with the sand paper 21c, the hollow rod 22 rotates, and at the same time, the brush 32 rotates together with the hollow rod 22, The brush 32 contacts the inner surface of the nozzle 7 and polishes the inner surface. By the polishing operation, foreign matters such as clad adhered to the inner surface of the nozzle 7 are removed.

  Therefore, not only the upper surface 7 a of the nozzle 7 but also the inner peripheral surface of the nozzle 7 can be cleaned with one polishing device 20.

  Thus, in any of the embodiments of the present invention, the activated cladding adhering to the upper surface 7a of the nozzle 7 of the internal pump 2 can be removed safely and reliably, and the diffuser 6 of the internal pump 2 can be removed of foreign matter. A seating surface that can be normally installed without biting can be secured on the upper surface 7 a of the nozzle 7.

  The present invention is applied to an apparatus for removing a clad adhering to the upper surface of an attachment nozzle of an internal pump of an improved boiling water reactor.

It is the longitudinal cross-sectional view of the internal pump attachment site | part to a nuclear reactor pressure vessel, and its internal pump. It is the longitudinal cross-sectional view which showed the condition which polishes the upper surface of the nozzle of the internal pump of FIG. 1 with the polisher by 1st Example of this invention. It is the longitudinal cross-sectional view of the nozzle vicinity which showed the condition which polishes the upper surface and inner peripheral surface of the nozzle of the internal pump of FIG. 1 with the polisher by 2nd Example of this invention. It is the figure which abbreviate | omitted and showed the camera in the top view of the polishing head part of the polishing apparatus by this invention. It is the longitudinal cross-sectional view which showed the condition which sealed the pump casing and nozzle after removing the component of the internal pump of FIG. 1 is an overall elevation view of a polishing apparatus according to a first embodiment of the present invention. It is a longitudinal cross-sectional view of the A arrow view part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel (bottom part), 2 ... Internal pump, 3 ... Pump part, 4 ... Motor part, 5 ... Impeller, 5a ... Impeller grip part, 5b ... Shaft, 6 ... Diffuser, 6a ... Diffuser boss part, DESCRIPTION OF SYMBOLS 7 ... Nozzle, a ... Upper surface of nozzle 7, 7b ... Nozzle taper part, 8 ... Stretch tube, 9 ... Pump casing, 10 ... Rotor, 11 ... Stator, 12 ... Stretch tube nut, 13 ... Secondary seal, 14 ... Motor cover , 15 ... Stud bolt, 16 ... Nut, 17 ... Nozzle upper plug, 18 ... Seal ring, 19 ... Grab part, 20 ... Polishing device, 21 ... Polishing head part, 21a ... Upper arm, 21b ... Lower arm, 21c ... Sand paper , 21d ... pin, 21e ... long pin, 21f ... collar, 22 ... hollow rod, 22a ... rotating handle, 22 ... Lock nut, 22c ... Stopper, 22d ... Connector, 22e ... Slide bearing, 23 ... Operating rod, 23a ... Head opening / closing handle, 24 ... Flange, 25 ... Screw, 25a ... Elevating handle, 26 ... Guide, 26a ... Guide bush 27 ... Drainage receptacle, 27a ... Drainage drain pipe, 28 ... Elevating screw, 28a ... Screw nut, 29 ... Drainage equipment, 30 ... Water supply equipment, 31 ... Lower closing flange, 32 ... Brush, 33 ... Camera.

Claims (6)

An expansion / contraction mechanism that can expand and contract between a width that can pass through the inside of the nozzle to which the diffuser of the internal pump is attached and a width that overlaps the upper surface of the nozzle;
A polishing material mounted at a position facing the upper surface of the nozzle of the telescopic mechanism;
Operating means for extending and contracting the expansion and contraction mechanism;
Rotating means for rotating the telescopic mechanism;
Elevating means for elevating the telescopic mechanism;
A base plate on which the lifting means is mounted;
Internal pump nozzle polisher equipped with.   2. The rotating means according to claim 1, further comprising: a rotating shaft fixed to the telescopic mechanism and rotatably attached to the elevating means; and a rotating handle fixed to the rotating shaft. An internal pump nozzle polishing apparatus, wherein the lifting / lowering means is mounted so as to pass through a vertical center line of a pump casing of a null pump.   3. The rotary shaft according to claim 2, wherein the rotary shaft has a hollow shaft structure, and a rod is inserted into the hollow of the rotary shaft so as to be movable in the axial direction of the rotary shaft, and the rod is the extension mechanism. An internal pump nozzle polishing device characterized in that the expansion / contraction mechanism has a link mechanism that converts the movement of the rod into an expansion / contraction operation of the expansion / contraction mechanism.   4. The internal pump nozzle polishing apparatus according to claim 3, wherein a brush is attached to the outer periphery of the rotating shaft so as to extend in the axial radial direction of the rotating shaft.   5. The nozzle upper plug according to claim 1, further comprising a nozzle upper plug that covers the upper portion of the nozzle of the internal pump and stops water, and the nozzle upper plug accommodates the upper surface of the nozzle and the expansion / contraction mechanism. An internal pump nozzle polishing apparatus characterized by having a structure having a space capable of being formed inside. From the pump casing provided in the reactor pressure vessel and the nozzle provided in the reactor pressure vessel, the components provided in the pump casing of the internal pump and the components provided in the nozzle The process of removing,
Attaching a plug to the nozzle after removing the parts of the internal pump so that the upper surface of the nozzle is contained inside, and sealing between the inside of the reactor pressure vessel and the inside of the nozzle; ,
Making the inside of the pump casing after the sealing into a gas atmosphere;
Polishing the upper surface of the nozzle in the gas atmosphere;
Internal pump nozzle polishing method equipped with.

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