JP3021808B2 - Inspection device for internal pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting an internal pump used in an improved boiling water reactor, and more particularly to a pump casing before a pump shaft of the internal pump is pulled upward and inspected underwater. The present invention relates to an internal pump inspection device that performs an aerial inspection in a room.

[0002]

2. Description of the Related Art In a conventional boiling water reactor, a feed water sparger is spread around the inner periphery of a reactor pressure vessel, and feed water entering the reactor pressure vessel from a feed water nozzle is uniformly mixed with high-temperature reactor water. are doing. A core shroud accommodating the core is provided in the reactor pressure vessel, and a jet pump is installed at equal intervals in the circumferential direction between the outer peripheral side of the core shroud and the inside of the reactor pressure vessel. The coolant is forcibly fed from the external recirculation system to the jet pump, and the surrounding coolant is sucked by the jet pump by the sent coolant, and the coolant is forcibly circulated to the core from below the core shroud. I try to make it. The coolant fed into the core boils while passing through the core and becomes a gas-liquid two-phase flow. The reactor water that has become a gas-liquid two-phase flow is separated into steam and water by a steam separator above the upper lattice plate of the core, and the steam passes through a steam dryer and is sent to the turbine as high-temperature, high-pressure steam. I have.

In this type of boiling water reactor, a circulating pump of a reactor recirculation system for recirculating coolant is installed outside the reactor pressure vessel. There is a risk of reactor water leaking from

In the latest improved boiling water reactor,
An internal pump in which a recirculation pump is installed in a reactor pressure vessel and a pump impeller of the recirculation pump is driven by a water immersion motor has been adopted.

[0005] Fig. 5 shows a conventional internal pump of this type, in which a cylindrical stub tube 3 is provided integrally with a lower vessel 2 of a reactor pressure vessel 1 at circumferential intervals. The upper portion of the pump casing 4 is inserted into the stub tube 3 and is supported in a suspended state. A water immersion motor 5 which is a motor unit is housed in the pump casing 4, while a pump shaft 6 which is an output shaft of the motor 5 extends upward together with the stretch tube 7 in the pump casing 4 to extend the reactor pressure vessel 1. And a pump impeller 8 which is a pump portion at its upper end.
Is attached.

The pump impeller 8 is housed in a diffuser 11 provided in a downcomer section 10 between the reactor pressure vessel 1 and the core shroud 9. The pump impeller 8 is driven to rotate via the pump shaft 6 by the drive of the water immersion motor 5, and the drive of the pump impeller 8 guides the reactor water located in the downcomer section 10 below the core, and upwards from below the core. It is turned over and forced into the core.

On the other hand, a motor cover 12 is provided at the lower end of the pump casing 4. By removing the motor cover 12, the water immersion motor 5 can be taken out of the pump casing 4. Even if the water immersion motor 5 is removed from the pump casing 4, the pump casing 4 is isolated from the reactor water in the reactor pressure vessel 1 by a water seal device (not shown), and the reactor water does not enter the pump casing 4.

[0008]

In the conventional internal pump, a water seal device is provided in the stub tube 3 to prevent reactor water from entering the pump casing 4, but a periodic inspection is performed. When the pump impeller 8 and the pump shaft 6 are pulled out upward in the work, the water seal device is broken, and the reactor water flows into the pump casing 4.

By the way, conventionally, the inspection of the pump impeller 8 and the pump shaft 6 is performed by pulling them upward,
Underwater inspection is performed in the reactor water, but the underwater inspection is not easy. For this reason, if the aerial inspection of the pump shaft 6 can be performed in the pump casing 4 before the water seal device is broken, it is expected that a large labor saving of the maintenance and inspection work can be expected.

The present invention has been made in view of the above circumstances, and provides an internal pump inspection apparatus capable of easily and reliably performing an air inspection of a pump shaft in a pump casing. With the goal.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an inspection apparatus for an internal pump according to the present invention is configured such that a water immersion motor of an internal pump is pulled out of a pump casing and then inserted into the pump casing. ,
An internal pump inspection device for inspecting the outer peripheral surface of a pump shaft located in a pump casing in the air, and a cylinder device installed at a position below the pump casing, and driving of the cylinder device, A cylindrical piston shaft that moves up and down the outer periphery of the pump shaft;
A camera rotation mechanism is provided at the top of the piston shaft and moves the TV camera around the pump shaft.

[0012]

In the inspection apparatus for an internal pump according to the present invention, after the water immersion motor is pulled out of the pump casing, the piston shaft is extended by driving the cylinder device. Then, the piston shaft moves up the outer peripheral portion of the pump shaft located in the pump casing, and the TV camera at the top of the piston shaft faces the pump shaft. After positioning the TV camera in the axial direction by raising and lowering the piston shaft, or when starting the camera rotation mechanism while raising and lowering the TV camera, the TV camera moves around the pump shaft and performs an aerial inspection of the outer peripheral surface of the pump shaft. be able to.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
This will be described with reference to FIG.

FIG. 1 shows an example of an inspection device for an internal pump according to the present invention. The inspection device 20 has a cylinder device 21 that moves the inspection device 20 up and down. The cylinder device 21 includes a cylindrical cylinder 22 and a cylindrical piston shaft 2.
3 for driving the cylindrical piston shaft 23 to expand and contract within the cylindrical cylinder 22.

The cylindrical piston shaft 23 is connected to the pump shaft 6
(See FIG. 5). The outer peripheral portion of the cylindrical piston shaft 23 has a piston portion 23 as shown in FIG.
a is provided integrally, and the space between the piston portion 23a and the inner peripheral surface of the cylindrical cylinder 22 is sealed in a liquid-tight manner by an O-ring (not shown).

At the lower end of the cylindrical piston shaft 23, that is, at the left end in FIG. 1, a saucer 24 having a drain plug 25 at the center is detachably screwed.

On the other hand, as shown in FIG. 1, an inner flange portion 22a is provided integrally with the upper end portion of the cylindrical cylinder 22, and the inner flange portion 22a and the cylindrical piston shaft 23 are provided.
The space between the outer peripheral surface and the outer peripheral surface is sealed by an O-ring.

In the lower end of the cylindrical cylinder 22,
As shown in FIG. 1, a ring 26 is screwed and fixed in a flange shape, and between the ring 26 and the inner peripheral surface of the cylindrical cylinder 22 and between the outer peripheral surface of the cylindrical piston shaft 23 are O-rings (not shown). Sealed. Then, by supplying pressurized water into the cylinder device 21 from a lower port 27 which is a plug seat provided on the cylindrical cylinder 22, the cylindrical piston shaft 23 is extended and the cylindrical cylinder 2 is extended.
By supplying pressurized water into the cylinder device 21 from an upper port 28 which is a plug seat provided in the cylinder 2, the cylindrical piston shaft 23 is contracted. The stroke of the cylindrical piston shaft 23 is set to a dimension l as shown in FIG.

The outer periphery of the lower end of the cylindrical cylinder 22 is shown in FIG.
As shown in the figure, a flange 29 is welded, and a flange 31 welded to the upper end of a cylindrical frame 30 is bolted to the flange 29.
The lower end of the reduced cylindrical piston shaft 23 is accommodated in the frame 30.

A base 32 is welded to the lower end of the frame 30 as shown in FIG.
Numeral 2 is installed on a platform or a pump casing immediately below the pump shaft 6 when performing an aerial inspection of the pump shaft 6 (see FIG. 5) using the inspection device 20.

As shown in FIG. 1, a ring plug-like flange 33 is welded to the upper end of the cylindrical piston shaft 23, and a TV camera 34 is turned around the pump shaft 6 on this flange 33. Rotating mechanism 34 for
Is installed.

As shown in FIGS. 1 and 2, the camera rotating mechanism 35 includes a cylindrical shaft 36 having an inner diameter into which the pump shaft 6 can be inserted, and a motor 37 for driving the cylindrical shaft 36 to rotate. The lower end of the motor casing 38 is fixed to the flange 33 with bolts or the like.

At the upper end of the motor casing 38,
As shown in FIG. 1, a sleeve-shaped internal gear 39 is fixed by bolts or the like. Inside the internal gear 39, as shown in FIGS. For example, three intermediate gears 40 simultaneously meshing with a gear portion 36 a formed on the outer surface of the outer gear 36 are arranged at equal intervals, and a pin 41 supporting each intermediate gear 40 is attached to a rotating drum 42.

As shown in FIGS. 1 and 3, the rotary drum 42 is formed in a disk shape.
Is fixed to the outer periphery of the cylindrical shaft 36 so as to rotate integrally therewith, and is prevented from coming off from the cylindrical shaft 36 by a washer 43 also serving as a thrust collar and a double nut 44 screwed onto the cylindrical shaft 36. As shown in FIG. 1, a thrust collar 45 is interposed between each intermediate gear 40 and the motor casing 38 so that each intermediate gear 40 can slide on the motor casing 38 smoothly. It has become.

As shown in FIGS. 1 and 3, the rotary drum 42 has two storage holes 4 at positions opposed to each other in the radial direction, for example.
The TV camera 34 is inserted into each of the storage holes 46 toward the axial center side, and is fixed by a holding plate 47. As shown in FIG. 1, these TV cameras 34 can capture the outer peripheral surface of the propeller shaft 5 (see FIG. 5) as an image through an opening 48 provided in the cylindrical shaft 36. The obtained image signal is transmitted to a remotely installed display device (not shown) and displayed.

Next, the operation of the inspection device for the internal pump will be described.

At the time of periodic inspection of the reactor, the internal pump shown in FIG. 5 is disassembled, inspected, and maintained.

At this time, first, the motor cover 12 is removed, and the water immersion motor 5 is taken out from the pump casing 4 onto the lower platform below. In this removal state, the water sealing device in the stub tube 3 portion is active, so there is no leakage of reactor water.

With the water immersion motor 5 removed from the pump casing 4, the inspection device 20 is installed immediately below the internal pump, and the cylinder piston 21 is raised by driving the cylinder device 21. Then, as shown in FIG. 4, the cylindrical piston shaft 23 and the camera rotating mechanism 35 are inserted into the pump casing 4 with the pump shaft 6 inserted.

When the motor 37 is started after the elevating device for the cylindrical piston shaft 23 is fixed, the TV camera 34 rotates around the pump shaft 6 at a predetermined reduction ratio, and a visual inspection of the outer peripheral surface of the pump shaft 6 is performed. .

By performing this operation by sequentially moving the axial position of the TV camera 34 by moving the cylindrical piston shaft 23 up and down, the entire outer peripheral surface of the pump shaft 6 can be visually inspected.

After the aerial inspection of the outer peripheral surface of the pump shaft 6 is completed, the inspection device 20 is removed, the lower end of the pump casing 4 is sealed with a water leakage tray or the like, and the inside of the pump casing 4 is filled with fresh water. After that, the pump impeller 8 and the pump shaft 6 are pulled out upward, and an underwater inspection is performed on a portion where the aerial inspection was not possible.

After all the inspections are completed, the internal pump is assembled in the state shown in FIG. 5 by the reverse procedure.

Although the underwater inspection is inferior in work efficiency and inspection accuracy as compared with the aerial inspection and is not easy, the underwater inspection is performed by inspecting most of the pump shaft 6 in the aerial inspection. Is greatly reduced, and a significant labor saving can be achieved as a whole of the internal pump regular inspection work.

It is desirable that the work at the reactor bottom be performed in a small work space and be automated because of the problem of radiation exposure. However, the inspection device 20 according to the present embodiment is configured to move the cylindrical piston shaft 23 up and down, 34 rotation and TV
Since the monitoring by the camera 34 and the like can all be performed remotely, it is suitable for furnace bottom work.

In the above embodiment, the internal gear 3
Although the case where the TV camera 34 is decelerated and rotated with respect to the motor 37 using the intermediate gear 9 and the intermediate gear 40 has been described,
If the motor 37 itself can rotate at low speed, the TV camera 34 may be directly fixed to the cylindrical shaft 36. Thus, the mechanism of the camera rotation mechanism 35 is
It can be more simplified.

[0037]

As described above, the internal pump inspection apparatus according to the present invention can be moved up and down in the pump casing with the water immersion motor removed from the pump casing, and the outer peripheral surface of the pump shaft. To
Since the aerial inspection can be performed in the pump casing, the underwater inspection of the internal pump can be reduced, and a large labor saving can be achieved in the regular inspection work as a whole.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an internal pump inspection apparatus according to the present invention.

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

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

FIG. 4 is an explanatory diagram showing a state during an aerial inspection by the inspection device.

FIG. 5 is a sectional view showing a configuration of an internal pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reactor pressure vessel 3 Stub tube 4 Pump casing 5 Water immersion motor 6 Pump shaft 8 Pump impeller 9 Core shroud 11 Diffuser 12 Motor cover 20 Inspection device 21 Cylinder device 22 Cylindrical cylinder 23 Cylindrical piston shaft 30 Frame 33 Flange 34 TV camera 35 Camera rotation mechanism 36 Cylindrical shaft 37 Motor 39 Internal gear 40 Intermediate gear 42 Rotary barrel

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Shigeru Watanabe 4-7-7 Shiba, Minato-ku, Tokyo Inside Aitel Technical Service Co., Ltd. (56) References JP-A-4-343094 (JP, A) JP-A Heisei 2-23296 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G21C 17/00 G21C 15/243 520 G21C 19/02 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. A device for inspecting an internal pump in which the water immersion motor of the internal pump is drawn out of the pump casing and then inserted into the pump casing, and the outer peripheral surface of the pump shaft located in the pump casing is inspected in the air. And a cylinder device installed at a position below the pump casing, a cylindrical piston shaft that moves up and down the outer peripheral portion of the pump shaft by driving the cylinder device, and is installed at a top portion of the piston shaft. An inspection apparatus for an internal pump, comprising: a camera rotating mechanism for moving a TV camera around a pump shaft.