JP3321498B2 - Secondary seal attachment / detachment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal pump provided in an improved boiling water reactor, and more particularly, to a secondary seal attaching / detaching apparatus capable of easily replacing a secondary seal.

[0002]

2. Description of the Related Art An improved boiling water reactor (hereinafter referred to as ABWR)
That. In), a plurality of internal pumps are attached to the reactor pressure vessel, and the internal pump forcibly recirculates the reactor water in the reactor.

[0003] The internal pump provided in the ABWR is configured as shown in FIG. 10 and is composed of a motor unit 1 and a pump unit 2. The rotational driving force from the motor unit 1 is transmitted through a drive shaft 3 to the pump unit. 2 and the pump unit 2
Is driven to rotate.

The pump section 2 has a diffuser 6 installed in an annular downcomer section 5 and a pump impeller 4 housed in the diffuser 6, and the pump impeller 4 is mounted on the top of the drive shaft 3 so as to rotate integrally therewith.

On the other hand, the motor unit 1 comprises a stator 7 and a rotor 8
And housed in the motor casing 9.
The upper part (neck) of the motor casing 9 is the reactor pressure vessel 1.
No. 0 is fixed to the nozzle 11 protruding from the lower mirror portion 10a by welding or the like, and is vertically provided. At the top of the nozzle 11 is the pump 2
The diffuser 6 is mounted on the nozzle 11 by a stretch tube 13 and a tube nut 14.

The stretch tube 13 is inserted into the neck of the motor casing 9, and the lower end thereof is fastened and fixed by a stretch tube nut 14. The drive shaft 3 is inserted into the stretch tube 13 from above,
The lower portion of the drive shaft 3 is inserted into and fixed to the rotor 8 of the motor unit 1 so that the rotational driving force of the motor unit 1 is transmitted.

A stretch tube nut 14 is provided on a shoulder 15 of the motor casing 9, and a secondary seal mechanism 16 (hereinafter referred to as a secondary seal) is mounted below the stretch tube nut 14. Secondary seal 1
6, a secondary seal pressurizing pipe 17 is provided on the back side,
Water pressure is applied to the back side of the secondary seal 16 via the pressurizing pipe 17 so that the elastomer constituting the sealing means of the secondary seal 16 is pressed into contact with the drive shaft 3 for sealing.

Further, a primary seal is formed by a metal contact between the collar portion of the drive shaft 3 and the upper surface 13a of the stretch tube 13. The primary seal seals the reactor water to prevent the leakage of the reactor water. ing.

Cooling water circulating pipes 19 are attached to the upper and lower portions of the body 18 of the motor casing 9, and the cooling water circulating pipes 19 are used to forcibly circulate the cooling water into the motor section 1 so that the motor section 1 is rotated. Cools to prevent its burning.

[0010] Maintenance work of the internal pump is performed at the time of periodic inspection of the ABWR. In a conventional internal pump, normal maintenance and inspection work is performed as follows.

In the maintenance and inspection work of the internal pump, the motor unit 1 is first removed from the motor casing 9. When the motor unit 1 is removed, the drive shaft 3 and the stretch tube 13 are connected to each other in order to prevent leakage of reactor water. Constitute a primary seal between the two.

Then, pressurized water is supplied from the secondary seal pressurizing pipe 17 to pressurize the back side of the secondary seal 16, and the elastomer is brought into close contact with the drive shaft 3, and the gap between the motor casing 9 and the drive shaft 3 is formed. Seal and shut off the reactor water in the reactor pressure vessel 10.

After the secondary sealing, the lid (closed) flange 20 of the motor casing 9 is removed, and the motor unit 1 is removed from below the casing.

After the motor unit 1 is detached from the motor casing 9, a closing flange 20 is attached to the motor casing 1 to seal the inside of the motor casing 9, and in this sealed state, the inside of the motor casing 9 is filled with makeup water. After the motor casing 9 is filled with makeup water, the secondary seal 1
Release 6.

When the secondary seal is released, the reactor pressure vessel 10
, The pump impeller 4 is pulled out together with the drive shaft 3 and removed. Removal of the pump impeller 4 and the drive shaft 3 is performed using a lifting machine on the refueling machine.

After the pump impeller 4 and the drive shaft 3 are removed above the reactor pressure vessel 10, the diffuser 6
Is closed with an upper plug 21 shown in FIG. In this sealed state, the makeup water in the motor casing 9 is discharged, and in this discharged state, the closing flange 20 of the motor casing 9 is removed.

After the closing flange 20 has been removed, the secondary seal 16 is removed using a replacement rotary base of the control rod drive mechanism, and maintenance, inspection, and repair of the secondary seal 16 are performed.

After the secondary seal 16 has been removed from the motor casing 9 downward, a closing flange 20 is attached to the lower end of the motor casing 9 and the inside of the motor casing 9 is filled with makeup water again. The upper plug 21 is removed from above the reactor pressure vessel 10 while being filled with make-up water.

After the inspection, repair and maintenance of the removed motor part 1 and the secondary seal 16 of the internal pump, the motor part 1, the pump impeller 4, the drive shaft 3 and the secondary seal 16 are attached again. The mounting of the internal pump is performed in the reverse procedure to the removal of the pump.

Thus, the maintenance and maintenance of the internal pump
The inspection / maintenance work is divided into an upper part and a lower part of the reactor pressure vessel 10, and the work is performed. The upper part of the reactor pressure vessel 10 is carried out by using a lifting machine on a refueling machine as described in JP-A-58-14092, and the lower part is described in JP-A-62-96896. This is performed by using a replacement rotary base or the like of the control rod drive mechanism as described above.

[0021]

In the maintenance and inspection work of the internal pump, the work of removing and installing the pump impeller 4 and the drive shaft 3 and the work of installing and removing the upper plug 21 are performed using a lifting machine of the refueling machine. Therefore, while it takes a long time to attach and detach the fuel assembly, it cannot be used while the fuel assembly is being exchanged by the fuel exchanger, and the operation cannot be performed. Similarly, during inspection work of the control rod drive mechanism, the rotary gantry cannot be used, and the work of removing and attaching the secondary seal 16 cannot be performed.

On the other hand, the secondary seal 16 applies a water pressure from the back side of the elastomer constituting the seal portion, presses the elastomer against the surface of the drive shaft 3 to seal the same, and pressurizes the reactor water in the reactor pressure vessel 10. The secondary seal 16 is used to prevent water leakage and to be worn or degraded due to long-term use. Therefore, the secondary seal 16 needs to be periodically replaced due to the life of the elastomer. You.

However, even when only the replacement of the secondary seal 16 is necessary, the conventional internal pump basically requires the maintenance-free removal and installation of the pump impeller 4 and the drive shaft 3 and the installation of the upper plug 21. Mounting ・
Removal work is required. Moreover, the work of attaching and detaching the pump impeller 4 and the upper plug 21 cannot be performed while the fuel assembly is being replaced, so that the operation has to wait.

For this reason, in the conventional internal pump, the replacement operation of the secondary seal 16 is strongly affected by the replacement operation of the fuel assembly and the maintenance / inspection operation of the control rod drive mechanism, or the replacement of the secondary seal. When performing only the above, it is necessary to attach and detach the pump impeller 4 and the upper plug 21.
The extra work which is not directly related to the attachment / detachment work of the secondary seal 16 requires a long time for the maintenance and inspection work of the internal pump, which causes a reduction in the operation rate of the reactor. I was

The present invention has been made in view of the above circumstances, and separates and detaches the operation of attaching and detaching the secondary seal mechanism from the operation of attaching and detaching the pump impeller, thereby further reducing the time required for maintenance and inspection of the internal pump. It is an object of the present invention to provide a secondary seal attaching / detaching device capable of shortening and improving the operation rate of a nuclear reactor.

Another object of the present invention is to make it possible to exchange the secondary seal mechanism without attaching and detaching the pump impeller and the drive shaft. It is an object of the present invention to provide a secondary seal attaching / detaching device which can be performed.

[0027]

According to the present invention, there is provided a secondary seal attaching / detaching apparatus according to the present invention. A mounting flange detachably attached to a lower part of a motor casing of the installed internal pump, a holding cylinder provided on the mounting flange, a hollow shaft mounted on the holding cylinder so as to be capable of ascending and descending, and a hollow shaft. An engagement claw provided at an upper portion and engaged with the secondary seal mechanism;
A cover sleeve provided by being urged upward from the upper portion of the hollow shaft and formed so that the upper portion expands, a rotating mechanism for rotating and driving the hollow shaft, and a drive shaft of a pump impeller provided on the mounting flange are downwardly provided. And a tension applying means for applying a tensile force.

[0028]

The secondary seal attaching / detaching device according to the first aspect operates as follows when removing the secondary seal mechanism at the bottom side of the stretch tube 13 of the internal pump. First, the mounting flange 52 is mounted on the lower portion of the motor casing 9 while the drive shaft 3 that is located below the internal pump 23 is inserted into the hollow shaft 56.

The tension applying means 78 is provided below the drive shaft 3.
And pull it down. Thereby, the seal by the temporary seal above the secondary seal mechanism 36 is strengthened.

The hollow shaft 56 is raised and then rotated to engage the engaging claw 71 with the secondary seal mechanism 36.
At this time, the washer 45 fixing the secondary seal mechanism 36 is pushed up at the upper end of the cover sleeve 77 and removed.

With the secondary seal mechanism 36 engaged with the engaging claw 71 and the washer 45 engaged with the cover sleeve 77, the mounting flange 52 is removed, and the entire detaching device for the secondary seal mechanism 36 is pulled out of the motor casing 9. .

As described above, according to this embodiment, the secondary seal mechanism 36 can be easily and reliably removed or attached from the motor casing 9 while the drive shaft 3 of the pump impeller 4 is mounted. The detachment or replacement work of the secondary seal mechanism 36 is separated from the refueling work and the maintenance and inspection work under the reactor pressure vessel without being affected by the refueling work and the maintenance and inspection work of the control rod drive mechanism. The operation time required for maintenance and inspection of the internal pump can be greatly reduced. Therefore, the operation rate of the nuclear reactor can be improved.

Further, the secondary seal attaching / detaching device according to the first aspect is capable of exchanging the secondary seal mechanism 36 without removing the pump impeller 4 or the drive shaft 3 without removing it. The replacement work of the next seal mechanism 36 can be simplified, and can be performed efficiently and economically in a short time.

[0034]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

In the improved boiling water reactor (ABWR),
As shown in FIG. 1, a plurality of wet motor type internal pumps 23 are provided in a reactor pressure vessel 10 housed in a reactor containment vessel 22. The internal pump 23 is provided in the vicinity of the lower mirror portion of the reactor pressure vessel 10, forcibly recirculates the reactor water in the reactor pressure vessel 10 by its pump action, and the core 2 surrounded by the core shroud 25.
6 is actively supplying reactor water.

The reactor core 26 is constructed by mounting a large number of fuel assemblies 27, while the reactor water heated by passing through the reactor core 26 is separated into gas and liquid by a steam separator 28. The separated steam is dried in the steam dryer 29, turned into dry steam, and guided to the main steam system 30.

On the other hand, the liquid separated by the steam separator 28 is guided to the annular downcomer 5 formed by the core shroud 25 and the inner peripheral wall of the reactor pressure vessel 10.
Water guided to downcomer part 5 is internal pump 2
It is recirculated by 3, guided to the lower plenum 31 of the core, and returned to the core 26 again.

The control rods 3 are provided between the fuel assemblies 27 of the core 26.
2 is moved in and out by the control rod drive mechanism 33, and ABWR
Start / stop and output control during operation.

On the other hand, the lower mirror portion 10a of the reactor pressure vessel 10
Since the overall structure of the internal pump 23 installed in is not different from that shown in FIG. 10, the same reference numerals are given and the description is omitted.

At the time of maintenance and inspection of the internal pump 23, maintenance and inspection / maintenance work is performed using the attachment / detachment device 35 of the internal pump 23.

In the internal pump 23, a secondary seal mechanism 36 is provided on the shoulder 15 of the motor casing 9 as shown in FIG. The secondary seal mechanism 36 is provided below the stretch tube nut 14 at a predetermined interval.

As shown in FIG. 3, the secondary seal mechanism 36 has a ring-shaped or torus-shaped seal body 37 mounted on the inner peripheral wall of the shoulder of the motor casing 9 in a liquid-tight manner with an O-ring or the like. Reference numeral 37 denotes upper and lower ring-shaped main body pieces 38 and 39 which can be divided into two parts, which are fastened by tightening bolts 40 or the like, and are integrated in a liquid-tight manner with an O-ring or the like.

In the seal body 37, a wedge-shaped seal guide surface is formed on the inner peripheral side by the mating surface of the main body pieces 38 and 39, and a sealing means is formed in a wedge-shaped ring-shaped tapered space 41 defined by the seal guide surface. Elastomer 4 as
3 are accommodated. The elastomer 43 is housed so as to protrude to the inner peripheral side, and fluid pressure such as air pressure or water pressure acts on the back side of the elastomer 43 from the secondary seal pressurizing pipe 17 via the communication passage 44. .

The seal body 37 has a washer 45 constituting an engagement holding means sandwiched between upper and lower body pieces 38 and 39. The washer 45 is formed of a disc spring or the like made of an elastic material. The inner peripheral side of the washer 45 is sandwiched between the main body pieces 38 and 39, and the outer peripheral side of the washer 45 engages with the peripheral groove 46 of the motor casing 9 to engage in the secondary sealing mechanism. 36 is held.

A connecting means 47 is provided below the seal body 37 of the secondary seal mechanism 36. The connecting means 47 comprises a disk-shaped engaging plate 48 and an engaging hole (groove) 49 formed integrally with the lower main body piece 39 of the seal main body 37.
Are detachably connected.

The secondary seal handling tool 50 is inserted from below the motor casing 9 as shown in FIG. 2, and the mounting flange 52 of the handling tool body 51 is attached to the lower flange portion 9a of the motor casing 9 by tightening bolts 53 or the like. It is fixed by a fastening means and is liquid-tightly installed by a sealing means such as an O-ring 54.

The handling tool 51 is integrally provided with a sleeve-like or tubular holding cylinder 55 which rises from the mounting flange 52. The holding cylinder 55 is provided with a hydraulic cylinder mechanism 57 as an elevating means for elevating and lowering the hollow shaft 56. ing. The hydraulic cylinder mechanism 57 is divided into an upper cylinder chamber 60 and a lower cylinder chamber 61 by a piston 58 provided on a lower outer peripheral side of the hollow shaft 56.
Hydraulic pressure is supplied to 0 and 61 by hydraulic lines 62 and 63. Even if the lifting / lowering means is a cylinder mechanism using water pressure or air pressure instead of the hydraulic cylinder mechanism 57,
A motor drive mechanism combining a motor and a screw shaft may be used.

The secondary seal handling tool 50 has a cylindrical space 65 inside which the drive shaft 3 can be inserted by the holding cylinder 55 and the hollow shaft 56, while the hollow space 56 has a circumferentially outer portion. The teeth 66 are formed, and the external teeth 66 mesh with the drive pinion 68 attached to the output shaft of the motor 67, and the rotation mechanism 6 of the hollow shaft 56
9. By driving the rotation mechanism 69, the hollow shaft 56 is driven to rotate about the shaft axis.

An engaging cylinder 70 is provided on the upper part of the hollow shaft 56, and a plurality of hook-shaped engaging claws 71 are provided on the upper part of the engaging cylinder 70 as shown in FIG. The engaging claw 71 may be formed directly on the top of the hollow shaft 56. The engaging claw 71 and the rotating mechanism 69 constitute a connecting means 72 for detachably connecting the upper portion of the hollow shaft 56 to the secondary seal mechanism 36. In addition, the engagement cylinder 7
The engagement release means of the secondary seal mechanism 16 is constituted by the zero or hollow shaft 56 and the hydraulic cylinder mechanism 57 which is the elevating means.

Further, the secondary seal mechanism 36 is provided in the engagement cylinder 70.
An engagement release holding means 74 for holding the engagement holding means 45 in the disengaged state is provided. The engagement release holding means 74 may be provided on the upper part of the hollow shaft 56. The engagement release holding means 74 includes a cover tube 75 which is slidably fitted to the engagement tube 70. The cover tube 75 is always urged upward by a spring 76 and is formed at the upper end of the cover tube 75. The cover sleeve 77 has an outer diameter that is slidably inserted into the shoulder 15 of the motor casing 9. The tapered end of the cover sleeve 77 is formed so as to expand toward the distal end.
The washer 45 as the engagement holding means is smoothly guided into the cover sleeve 77 when the engagement holding means 45 of 6 is released.

On the other hand, the secondary seal handling tool 50 is provided with a tension applying means 78 for applying a tensile force to the drive shaft 3 at the center of the mounting flange 52 as shown in FIG.
The tension applying means 78 includes an adjusting bolt 79 which is attached to the center hole of the mounting flange 52 in a liquid-tight manner. The tip of the adjusting bolt 79 is screwed to an impeller pad 80 extending downward from the drive shaft 3. Then
By rotating the adjustment bolt 79, the impeller pad 80 is pulled downward, and applies a downward pulling force to the drive shaft 3. As shown in FIG. 10, the primary seal of the internal pump 23 is brought into contact with the metal to seal the reactor water by this tensile force.

Thus, the internal pump 23 is provided with the elastomer 4 constituting the sealing means of the secondary sealing mechanism 36.
Periodical replacement is required due to the life of 3. In the case of the conventional internal pump, when the elastomer of the secondary seal mechanism 16 is exchanged, the operation of attaching and detaching the pump impeller and the operation of attaching and detaching the upper plug 21 are required. During the replacement work of 27, the secondary seal mechanism 16 could not be removed or attached.

The attachment / detachment device 3 for the internal pump 23
5, a secondary seal handling tool 50 is installed on the motor casing 9, and by operating the secondary seal handling tool 50, the removal and attachment of the secondary seal mechanism 36 can be performed by attaching and detaching the pump impeller 4 and the upper plug 21. The operation can be performed independently from the lower side of the reactor pressure vessel 10 independently of the operation of attaching and detaching the pump impeller 4.

Next, the operation of the attachment / detachment device 35 for the internal pump 23 will be described.

The attachment / detachment device 3 for the internal pump 23
When the attachment / detachment work of the secondary seal mechanism 36 is performed by using the fluid seal 5, the fluid pressure is applied from the secondary seal pressurizing pipe 17 to the back side of the secondary seal mechanism 36 so that the elastomer 43 as the sealing means is driven by the drive shaft 3 is pressed against and sealed to prevent leakage of reactor water in the reactor pressure vessel 10.

In this state, the closing flange 20 of the internal pump 23 is removed, the motor unit 1 is taken out from below the motor casing 9, and maintenance and inspection and maintenance of the motor unit 1 are performed.

After removing the motor unit 1 from the motor casing 9, the secondary seal handling tool 50 is
Of the mounting flange 52 and the fastening bolt 53
And the secondary seal handling tool 50 is fixed to the lower portion of the motor casing 9. At this time, the impeller pad 80 extending downward from the drive shaft 3 is screw-coupled by the tension applying means 78 to apply a downward tensile force to the drive shaft 3 to strengthen the close contact with the primary seal. In this state, the sealing function of the secondary sealing mechanism 36 is released. The removal and attachment of the secondary seal mechanism 36 is performed with the pump impeller 4 and the drive shaft 3 mounted as shown in FIG.

Next, when the hydraulic cylinder mechanism 57 of the secondary seal handling tool 50 is driven to move the hollow shaft 56 upward, the engagement claws 7 of the connecting means 72 are moved from the state shown in FIG.
1 enters the connecting means 47 below the secondary seal mechanism 36. Specifically, the engagement claws 71 enter the elongated holes of the engagement plate 48 of the secondary seal mechanism 36. The rotating mechanism 69 is driven to rotate the engaging claw 71 in a state where the engaging claw 71 is inserted into the elongated hole of the engaging plate 48, and the engaging claw 71 is engaged with the engaging hole 49. By this engagement, the engagement claw 71 is connected to and locked by the connection means of the secondary seal mechanism 36, and FIG.
As shown in (B), the drawing becomes impossible.

The secondary seal handling tool 50 is connected to the secondary seal mechanism 3
When the hydraulic cylinder mechanism 57 is driven again in the state of being connected to the connecting means 47 of No. 6 to further raise the hollow shaft 56 by a required amount, the entire secondary seal mechanism 36 is pushed up by the hollow shaft 56 and lifted. By lifting the secondary seal mechanism 36, the washer 45 of the engagement holding means is raised.
Is bent downward and inward while coming off the circumferential groove 46 of the motor casing 9. As a result, at the same time when the engagement between the washer 45 and the peripheral groove 46 of the motor casing 9 is released, the cover cylinder 75 is raised by the spring action of the spring 76, and the cover sleeve 77 closes the peripheral groove 46, and FIG. The state shown in FIG. At this time, the hydraulic cylinder mechanism 57 is
5 functions as an engagement releasing means.

With the cover sleeve 77 of the cover cylinder 75 closing the circumferential groove 46, the hydraulic cylinder mechanism 5 serving as the elevating means is
7 is driven again to move the hollow shaft 56 downward.
When the hollow shaft 56 is moved downward, the cover sleeve 77 of the cover cylinder 75 is
6, the washer 45 is guided and inserted into the cover sleeve 77 while being bent.

The cover sleeve 7 of the cover cylinder 75 is moved by the lowering operation of the hollow shaft 56 by the hydraulic cylinder mechanism 57.
7 restricts the spreading operation of the washer 45, so that the secondary sealing mechanism 36 does not obstruct the shoulder portion 1 of the motor casing 9 without any obstacle.
5 and is guided by the body 18 of the motor casing 9 (see FIG. 6D).

Thereafter, while the fastening bolt 53 of the secondary seal handling tool 50 is removed, the tension applying means 78 is operated to release the application of tension to the drive shaft 3, and a screw mechanism (not shown) is driven by a drive motor. The base (not shown) is lowered, and the secondary seal handling tool 50 installed on the base is pulled out from below the motor casing 9. Thus, the operation of removing the secondary seal mechanism 36 ends.

Thereafter, the removed secondary seal mechanism 36
Is performed, and the elastomer 43, which is a sealing means whose life has expired, is replaced. After the maintenance of the secondary seal mechanism 36, the secondary seal mechanism 36 is attached to the shoulder 15 of the motor casing 9 again.

The mounting operation of the secondary seal mechanism 36 is performed as follows.

The hollow shaft 56 of the secondary seal handling tool 50
Is held at the lowered position by the hydraulic cylinder mechanism 57, the cover cylinder 75 is removed in this state, and the secondary seal mechanism 36 is installed in a state where the secondary seal mechanism 36 is connected by the engagement claws 71.

Next, the drive motor is started to rotate a screw mechanism (both not shown) to raise the base, and the secondary seal handling tool 50 installed on the base is inserted into the motor casing 9. Then, the secondary seal handling tool 50 is fixed to the motor casing 9 by the fastening bolt 53 and is installed.

Further, the impeller pad 80 extending from the drive shaft 3 of the pump impeller 4 is connected to the tension applying means 78.
And the drive shaft 3 is fixed by screwing to the adjustment bolt 79 of FIG. After fixing the drive shaft 3, the hydraulic cylinder mechanism 57 is driven to raise the hollow shaft 56, and the washer 45, which is the engagement holding means of the secondary seal mechanism 36, is moved in contact with the shoulder inner peripheral wall of the motor casing 9. Is engaged with the peripheral groove 46 of the motor casing 9. This washer 4
By the engagement of 5, the secondary seal mechanism 36 is forcibly mounted on the shoulder 15 of the motor casing 9 and is engaged and held.

Thereafter, the connection state between the secondary seal handling tool 50 and the secondary seal mechanism 36 is released by the driving of the rotation drive, and in this released state, the fastening bolt 53 of the secondary seal handling tool 50 is removed, and a drive (not shown) The motor is driven to pull out the secondary seal handling tool 50 from below the motor casing 9, and the work of mounting the secondary seal mechanism 36 is completed.

After the mounting of the secondary seal mechanism 36 is completed,
By inserting the motor unit 1 from below the motor casing 9 and closing the lower part of the motor casing 9 to close the flange 20, the maintenance and inspection work of the internal pump 23 is completed.

Next, a description will be given of a second embodiment of the secondary seal attaching / detaching device.

FIGS. 7 to 9 show a second embodiment of the secondary seal attaching / detaching device. In the attachment / detachment device 35A of the internal pump 23 shown in the second embodiment, the secondary seal handling tool 50A is inserted into the motor casing 9 from below, and is installed in a liquid-tight manner via the mounting flange 52.

The secondary seal handling tool 50A is provided with the mounting flange 5
The hollow cylinder 56 is housed in the holding cylinder 55 so as to be able to move up and down by the elevating means 85. The elevating means 85 is formed by, for example, a screw shaft mechanism 86 with a motor. The hollow shaft 56 is raised and lowered by rotating a screw shaft 88 by a reversible drive motor 87. A cylindrical space 90 through which the drive shaft 3 of the pump impeller 4 can be inserted is formed in the hollow shaft 56 and the holding cylinder 55.

A bearing 9 is provided above the hollow shaft 56.
1, an engagement cylinder 92 is provided rotatably around a central axis, and a rotation mechanism 9 for applying rotation to the engagement cylinder 92.
3 is provided on the upper part of the hollow shaft 56. Rotation mechanism 9
3 is constituted by engaging a drive pinion 95 attached to an output shaft of a drive motor 94 with an engagement tooth 96 provided on an outer peripheral side of an engagement cylinder 92. The rotation mechanism 93 may have the drive motor 94 provided on the engagement cylinder 92 side and the engagement teeth provided on the hollow shaft 56 side. The rotation mechanism 93 constitutes the disengagement holding means for disengaging the engagement holding means 101 of the secondary seal mechanism 100 shown in FIG. Since the rotation mechanism 93 only needs to rotate the engagement cylinder 92, the rotational inertia amount may be small.

On the other hand, an engagement claw 95 is provided at the top of the engagement cylinder 92. The engaging claw 95 is formed in a hook shape similar to that shown in FIG. 4, for example. Reference numeral 79 denotes an adjusting bolt of the tension applying means 78. The shape of the adjusting bolt 79 is not different from that shown in FIG.

The shoulder 15 of the internal pump 23
The secondary seal mechanism 100 mounted on the motor casing 9 has a ring-shaped structure shown in FIG. The secondary seal mechanism 100 has a ring-shaped seal main body 102, and the seal main body 102 can divide the ring-shaped upper main body piece 103, lower main body piece 104, and support body 105 by tightening a tightening bolt 106 together. It is assembled and integrated.

The seal body 102 of the secondary seal mechanism 100
Has a wedge-shaped seal guide surface on the inner peripheral side.
3, 104, while a wedge-shaped ring-shaped tapered space 107 defined by the seal guide surface.
, An elastomer 108 as a sealing means is accommodated therein. The elastomer 108 is housed so as to protrude inward on the inner peripheral side, while fluid pressure such as air pressure or water acts on the back side of the elastomer 108 from the secondary seal pressurizing pipe 17 via the communication passage 109. By the action of this fluid pressure, the elastomer 1
08 is pushed out and comes into pressure contact with the drive shaft 3 to perform a sealing action.

On the other hand, a support 105 is attached to a lower portion of the secondary seal mechanism 100, and a slide ring 110 is supported on the support 105 so as to be slidable in the rotation direction. The slide amount of the slide ring 110 is the tightening bolt 1
The slide ring 110 is formed with a plurality of engagement holes 112 that can be engaged with the engagement claws 95 of the engagement cylinder 92 while being regulated by the respective long holes 111 that engage with the reference numeral 06. Further, a plurality of projections projecting outward in the radial direction are formed on the slide ring, and a fixing pin 114 is provided on a free end side of the projection. Each fixing pin 114 is slidably engaged with a long hole 116 formed in an arcuate engagement arm 115. Each elongated hole 116 intersects at a predetermined angle with respect to the radial direction so as to have a helical spread.

Further, each of the engagement arms 114 is connected to the seal body 1.
02 is rotatably supported around a support pin 117 fixed to the support pin 02. In practice, each engagement arm 115 has its slot 11
Due to the engagement between the fixing pin 114 and the fixing pin 114, the supporting pin 117 is swingably supported in the horizontal direction around the support pin 117. Support pin 117
May be provided on the lower surface of the body piece 103 of the seal body 102 or on the support 105.

When the slide ring 110 is rotated counterclockwise from the state shown in FIG. 9A, the engagement arm 115 swings around the support pin 117 and expands.
The state shown in FIG. 9B is obtained. In the expanded state shown in FIG. 9B, the free end side of each engagement arm 115 engages with the circumferential groove 46 of the shoulder portion 15 of the motor casing 9, and the secondary seal mechanism 1
00 is held. Motor casing 9
A spring is interposed between the slide ring 110 and the support 105 so as to stably hold the secondary seal mechanism 100 on the shoulder portion 15, and the slide ring 110 is moved in the direction in which each engagement arm 115 expands. A spring may be always applied.

The secondary seal mechanism 100 is provided with each of the engagement arms 11
The engagement holding means 101 is formed by expanding the engagement arms 115 and engaging the engagement arms 115 with the circumferential grooves 46 of the motor casing 9 by rotating the slide ring 110. By this engagement holding means 101,
The secondary sealing mechanism 100 is provided on the shoulder 15 of the motor casing 9.
Is fixedly held.

The secondary seal mechanism 100 is configured as shown in FIG. 8 and FIG.
02, a connecting means 11 for connecting to the secondary seal handling tool 50A
9 are configured. The connecting means 119 is connected to the support 105
The engagement hole formed in the engagement hole 1 of the slide ring 110
12 is formed by allowing the engaging claws 95 of the secondary seal handling tool 50A to be freely inserted into these engaging holes 112.

The secondary seal mechanism 10 shown in FIGS. 8 and 9
The attachment / detachment work of 0 is performed as follows.

When removing the secondary seal mechanism 100 provided in the internal pump 23, first, a fluid pressure is applied to the back side of the secondary seal mechanism 100 to press the elastomer 108, which is a sealing means, against the drive shaft 3. Contact and seal to prevent reactor water leakage.

With the secondary seal mechanism 100 operated, the closing flange 20 of the motor casing 9 is removed, and the motor unit 1 is taken out from below the motor casing 9. The removal of the motor unit 1 is carried out using a replacement rotary gantry (not shown) of the control rod drive mechanism.

After the motor unit 1 is removed from the motor casing 9, a drive motor (not shown) is driven to rotate a screw mechanism to raise a base (not shown), and to mount a secondary unit installed on the base. The seal handling tool 50A is inserted into the motor casing 9 from below. At this time, the drive shaft 3 is inserted into the hollow shaft 56 of the secondary seal handling tool 50A so as to be guided.

After the secondary seal handling tool 50A is inserted, the secondary seal handling tool 50A is fixed to the motor casing 9 by the fastening bolt 53 and installed, while the impeller pad 80 extending from the drive shaft 3 of the internal pump 23 is mounted.
An adjusting bolt 79 as a tension applying means is screw-connected to the driving shaft 3 to apply a downward pulling force to the drive shaft 3 to strengthen the sealing function of the primary seal. By the screw connection of the adjusting bolt 79, the drive shaft 3 can be stably held without lateral deflection.

In this state, the drive motor 8
7 is driven to raise the hollow shaft 56, and the engaging claw 85 provided on the upper part of the hollow shaft 56 is inserted into the elongated hole of the support 105 formed on the lower part of the secondary seal mechanism 100. The engaging claw 85 and the elongated hole each constitute a connecting means.

After inserting the engaging claw 95 of the secondary seal handling tool 50A into the elongated hole constituting the connecting means 119 of the secondary seal mechanism 100, the rotating mechanism 93 is activated to view the engaging claw 95 from above. When rotated clockwise, the engagement claw 95 is locked to the support 105 so as not to be pulled out, and is connected thereto. Also,
When the slide ring 110 is rotated clockwise, the engagement arm 115 is moved from the expanded state shown in FIG.
It can be brought to the storage state shown in FIG.

When the slide ring 110 is rotated in the clockwise direction, the fixing pin 114 is turned into the long hole 11 of each engagement arm 115.
6, each engaging arm 115 is pulled inward and disengages from the peripheral groove 46 of the motor casing 9, and the engagement holding means 1 of the motor casing 9 and the secondary seal mechanism 100
01 is released.

In the state where the engagement of the secondary seal mechanism 100 is released, the drive motor 87 of the lifting / lowering means 85 is driven to lower the hollow shaft 56. At this time, since the secondary seal mechanism 100 has been disengaged from the circumferential groove 46 of the motor casing 9, the secondary seal mechanism 100 is taken out without any obstacle, and the body 18 of the motor casing 9 is removed.
Will be guided to.

In this state, when the fastening bolt 53 of the secondary seal handling tool 50A is removed, and the drive motor (not shown) is driven to lower the base by the screw mechanism, the secondary seal handling tool installed on the base is removed. 50A to motor casing 9
It can be pulled down further. Thereby, the removal of the secondary seal mechanism 100 is completed, and the secondary seal mechanism 10 is removed.
Thereafter, the maintenance and inspection or replacement is performed, and after the maintenance and inspection or replacement, the mounting operation of the secondary seal mechanism 100 is started.

In the mounting operation of the secondary seal mechanism 100, the lifting / lowering means 85 is driven to set the hollow shaft 56 to the lower position, while the engagement arm 115 of the secondary seal mechanism 100 is rotated by the rotation of the slide ring 110. And set so that the engaging claw 95 can be inserted into the elongated hole of the support 105. Then, the secondary seal mechanism 100
9 is set on the secondary seal handling tool 50A, and the entire secondary seal mechanism 100 is rotated counterclockwise when viewed from above, and FIG.
From FIG. 9A, the engaging arm 115 is housed as shown in FIG. 9B.

Next, a drive motor (not shown) is driven to raise a base (not shown) by a screw mechanism, and the secondary seal handling tool 50A installed on the base is inserted into the motor casing 9 from below. I do. After inserting the secondary seal handling tool 50A, the secondary seal handling tool 50A is fixed to the lower flange portion 9a of the motor casing 9 with the fastening bolt 53,
install. When the secondary seal handling tool 50A is installed, the adjusting bolt 79 of the tension applying means 78 is screwed to the impeller pad 80 of the drive shaft 3 so that the drive shaft 3
Is stably held.

After the drive shaft 3 is fixed and held, the lifting / lowering means 85 of the secondary seal handling tool 50A is driven to move the hollow shaft 56 upward to reach the shoulder 15 of the motor casing 9 of the secondary seal mechanism 100. .

After the secondary seal mechanism 100 reaches a predetermined position on the motor casing 9, the rotation mechanism 93 is driven to rotate the engagement cylinder 92 counterclockwise as viewed from above. This rotation of the engagement cylinder 92 causes the engagement arm 115 to expand and engage with the circumferential groove 46 of the motor casing 9, and the secondary seal mechanism 100 is attached to a predetermined position of the shoulder 15 of the motor casing 9. The engaging claw 95 can be pulled out from the elongated hole constituting the connecting means 119 of the support 105.

Thereafter, by removing the fastening bolt 53 of the secondary seal handling tool 50A and driving a drive motor (not shown), the secondary seal handling tool 50A can be pulled out from the lower portion of the motor casing 9, and the secondary sealing mechanism can be removed. The mounting work of 100 is completed.

According to the secondary seal attaching / detaching device, the attaching / detaching operation of the secondary seal mechanisms 36 and 100 can be performed independently of the attaching / detaching operation of the maintenance-free pump impeller 4 and the attaching / detaching operation of the upper plug 21. In addition, the work of attaching and detaching the secondary seal mechanism can be performed only by work below the reactor pressure vessel 10, and can be performed independently even during the work of replacing the fuel assembly.

Also, during the period of regular inspection of the ABWR, there is no need to detach and attach the pump impeller 4 and the drive shaft 3 which are maintenance-free. Can be. At the time of the periodic inspection of the ABWR, the elastomers 43 and 108 as the sealing means need to be replaced depending on the life. Therefore, the replacement of the elastomers 43 and 108 as the sealing means is performed at the time of attaching and detaching the secondary sealing mechanisms 36 and 100. It is.

In the second embodiment of the secondary seal attaching / detaching device according to the present invention, the example in which the engaging cylinder is rotated through the bearing above the hollow shaft is shown. Is not always necessary. If the hollow shaft itself can be rotated by the rotating mechanism with respect to the protection cylinder, the engagement cylinder and the bearing become unnecessary. In this case, the engaging claw may be provided directly on the upper part of the hollow shaft.

[0100]

As described above, the secondary seal attaching / detaching device according to the first aspect is provided with a hollow shaft for driving the holding cylinder provided on the mounting flange up and down, and provided on the upper portion of the hollow shaft. An engaging claw that engages the secondary seal mechanism;
A cover sleeve formed so that the upper part provided by urging upward from the upper part of the hollow shaft is expanded, a rotating mechanism for driving the hollow shaft to rotate, and a drive shaft of the pump impeller provided on the mounting flange are downwardly mounted. And a tension applying means for applying a pulling force to the motor casing, so that the secondary seal mechanism can be detached from the motor casing by the secondary seal handling tool while the drive shaft of the pump impeller is mounted. For this reason, the work time required for maintenance and inspection of the internal pump can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a principle view showing an improved boiling water reactor equipped with an internal pump.

FIG. 2 is a longitudinal sectional view showing one embodiment of a secondary seal attaching / detaching device according to the present invention.

FIG. 3 is a partial cross-sectional view showing an engagement relationship between a secondary seal handling tool and a secondary seal mechanism provided in the secondary seal attaching / detaching device according to the present invention.

FIG. 4 is a perspective view showing a connecting means of a secondary seal handling tool provided in the secondary seal attaching / detaching device according to the present invention.

FIG. 5 is a cross-sectional view showing a operable state of a secondary seal mechanism provided in the secondary seal attachment / detachment device according to the present invention.

6 (A) to 6 (D) are views showing a procedure for removing a secondary seal mechanism using the secondary seal attaching / detaching device according to the present invention.

FIG. 7 is a longitudinal sectional view showing another embodiment of the secondary seal attaching / detaching device according to the present invention.

FIG. 8 is a partial cross-sectional view showing an engagement relationship between a secondary seal mechanism and a secondary seal handling tool in the secondary seal shown in FIG. 7;

FIGS. 9A and 9B are plan views respectively showing an inoperative state (stored state) and an operating state (expanded state) of the engagement holding means of the secondary seal mechanism shown in FIG. 8;

FIG. 10 is a longitudinal sectional view showing an internal pump provided in the improved boiling water reactor.

FIG. 11 is a longitudinal sectional view showing a state in which a secondary seal mechanism using a conventional internal pump can be handled.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor part 2 Pump part 3 Drive shaft 4 Pump impeller 5 Downcomer part 6 Diffuser 7 Stator 8 Rotor 9 Motor casing 10 Reactor pressure vessel 11 Nozzle 13 Stretch tube 14 Stretch tube nut 15 Motor casing shoulder 16 Secondary seal mechanism 17 Secondary seal pressurized pipe 18 Body of motor casing 19 Cooling water circulation pipe 20 Closing (lid) flange 21 Upper plug 22 Reactor containment vessel 23 Internal pump 24 Core shroud 26 Core 32 Control rod 33 Control rod drive mechanism 35, 35A Internal pump attachment / detachment device 36 Secondary seal mechanism 37 Seal body 38, 39 Body piece 40 Tightening bolt 41 Tapered space 43 Elastomer 45 Washer (engagement holding means) 46 Circumferential groove 47 Connecting means 50 Secondary seal handling tool 51 Handling tool body 52 Mounting flange 55 Holding cylinder 56 Hollow shaft 57 Hydraulic cylinder mechanism (elevating / disengaging means) 58 Piston 60, 61 Cylinder chamber 65 Cylindrical space 67 Motor 68 Drive pinion 69 Rotation Mechanism 70 Engagement cylinder (engagement release means) 71 Engagement claw 72 Connection means 74 Engagement release holding means 77 Cover sleeve 78 Tension applying means 79 Adjusting bolt 85 Elevating means 86 Screw-shaft mechanism 87 Drive motor 88 Screw-shaft 90 Cylindrical space portion 91 Bearing 92 Engagement cylinder 93 Rotation mechanism (engagement release holding means) 95 Engagement claw 100 Secondary seal mechanism 101 Engagement holding means 102 Seal body 103 Upper body piece 104 Lower body piece 105 Support body 106 Tightening With bolt 107 Lenking Tapered space 108 elastomer 110 slide ring 111 long hole 112 engagement hole 114 fixing pin 115 engagement arm 116 long hole 117 support pin 119 connecting means

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroyuki Nojima 2 in 4 Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Keihin Plant (56) References JP-A-62-204190 (JP, A) 64-54292 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G21C 15/243 520 G21C 15/243 510 G21C 19/02

Claims (1)

(57) [Claims] 1. A mounting flange detachably attached to a lower part of a motor casing of an internal pump vertically suspended from a lower mirror portion of a reactor pressure vessel, a holding cylinder provided on the mounting flange, A hollow shaft mounted so as to be able to move up and down, an engaging claw provided on the upper portion of the hollow shaft to engage with the secondary seal mechanism, and an upper portion provided by being urged upward from the upper portion of the hollow shaft to expand the upper portion Mounting and dismounting a secondary seal including a cover sleeve formed so as to perform rotation of the hollow shaft, and a tension applying means provided on the mounting flange for applying a downward pulling force to the drive shaft of the pump impeller. apparatus.