JP2856610B2 - Inspection device for impeller 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 impeller for an internal pump suitable for inspecting the presence or absence of scars such as an impeller blade of a coolant recirculation pump (hereinafter, referred to as an internal pump) built in a nuclear reactor. .

[0002]

2. Description of the Related Art An improved boiling water reactor employs an internal pump in which a pump and a drive motor are integrated into a reactor pressure vessel.

[0003] The internal pump forcibly circulates a coolant in a reactor pressure vessel to effectively generate steam, and changes the flow rate of coolant supplied to the reactor core to change the heat output of the reactor (volume of generated steam). Is controlling.

FIG. 8 is a sectional view showing a wet motor type internal pump. The internal pump 1 includes a pump section 3 provided in a reactor pressure vessel 2 and a motor provided outside the reactor pressure vessel 2. 4.

[0005] The pump section 3 comprises a diffuser 9 fixed in the reactor pressure vessel 2 and an impeller 10 disposed so as to be surrounded by the diffuser 9. A diffuser wear ring around the impeller 10 side of the diffuser 9
11 is fixed.

As shown in FIGS. 4 and 5, the impeller 10 is composed of a plurality of blades (five in the figure) combined around a boss 10a.

The motor unit 4 comprises a rotor 6 attached to a shaft 12 in a pump casing 5 vertically provided at the lower bottom of the reactor pressure vessel 2, and a stator 7 provided opposite the rotor 6. ing. A main flange 8 is attached to the lower end of the pump casing 5 housing the rotor 6 and the stator 7 and hermetically sealed.

The impeller 10 and the shaft 12 are integrally connected. The shaft 12 extends to the motor unit 4 and
Are combined.

Therefore, during operation of the motor section 4, the rotational force of the rotor 6 is transmitted to the shaft 12, and the impeller 10 rotates. The rotation of the impeller 10 causes the reactor pressure vessel 2
The coolant inside is discharged from the diffuser 9 toward the lower part of the core.

Note that a collar portion 13 having an outer diameter one step larger is provided on the upper portion of the shaft 12. The collar portion 13 functions as a back sheet for preventing the coolant from flowing into the pump casing 5 at the time of periodic inspection of the motor portion 4.

A gap 14 is provided between the rotating impeller 10 and the diffuser wear ring 11 of the fixed diffuser 9.
Is provided. The impeller 10 has the rotor 6 on the shaft 12
Are connected and fixed. However, since the shaft 12 protrudes above the rotor 6, the rotor 6
When a slight imbalance occurs, the impeller 10 may be swung and the gap 14 may not be narrowed.

Since the impeller 10 has a plurality of blades attached to the shaft 12 like an impeller and rotates at a high speed, a scar or the like on the impeller and its blade surface not only adversely affects the pump performance, but also There is a possibility that fragments and the like are scattered in the reactor pressure vessel 2.

Therefore, conventionally, after the internal pump 1 has been operated for a certain period of time, the outer peripheral portion and the blade of the impeller 10 are inspected, and if there is any scar on the blade surface of the impeller 10, it is repaired. The rotation balance of the impeller 10 is adjusted. This inspection is performed during the periodic inspection of the nuclear power plant.

In this inspection procedure, first, the operation of the reactor is stopped, and the reactor pressure vessel 2 is filled with water to shield radiation. Then, the lid (not shown) of the reactor pressure vessel 2 is removed, and the reactor well (not shown) is filled with water to remove the reactor internals.

Next, the boss 10a at the upper end of the impeller 10 is grasped in water using an impeller lifting jig, the impeller 10 and the shaft 12 are lifted integrally by a hoist, taken out of the reactor pressure vessel 2, and Transport to the pool inside the reactor building connected to the reactor well.

Thereafter, the outer periphery of the blade of the impeller 10 and the outer periphery of the shaft 12 are observed in a television image using an underwater television camera while shielding radioactive substances attached to the blade of the impeller 10 in the pool water. Inspect for scars.

[0017]

In order to inspect the surfaces of the blades and the like of the impeller 10 using an underwater television camera, the impeller 10 and the shaft 12 are suspended in water, and the periphery of the blade of the impeller 10 is It is necessary to move the underwater television camera.

However, when the underwater television camera is moved underwater by remote control, it is difficult to keep the distance between the underwater television camera and the blade of the impeller 10 constant. In addition, it is difficult to work by inserting an underwater television camera into a narrow gap where one blade and the other blade are curved.

Therefore, there is a problem that clear image information cannot be obtained by the underwater television camera, and a scar formed on the surface of the blade or the like of the impeller 10 is missed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an impeller for an internal pump capable of accurately and reliably inspecting a fine scar formed on the surface of an impeller blade while the impeller and the shaft are stored underwater. An inspection apparatus is provided.

[0021]

SUMMARY OF THE INVENTION The present invention relates to an operation stand mounted on the upper surface of an impeller of an internal pump via rollers, a camera movably incorporated in the operation stand, and an optical axis of the camera. An inspection base provided above the operation base having adjustment, vertical position adjustment, and circumferential movement adjustment mechanisms.

[0022]

[Action] placing the impeller and the shaft of the internal pump to be examined in the storage rack in the reactor building pool as together to set the operating platform of underwater television camera on surfaces of the impeller is incorporated into a movable fashion .

A drive motor for scanning the underwater television camera by vertically moving and moving in the circumferential direction is incorporated in the inspection stand in advance. In addition, a drive motor for rotating the inspection gantry is incorporated.

By operating a control panel provided separately from the inspection apparatus, an underwater television camera is inserted between the blades of the impeller stored in advance, scanned, and moved to the inspection target position.

The surface of the impeller blades and the like is inspected by scanning the underwater television camera by moving the motor up and down or in the circumferential direction, or by rotating the inspection stand. At this time, the video of the underwater television camera is also recorded on the VTR, and a reliable inspection without any leakage is performed.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an inspection apparatus for an impeller for an internal pump according to the present invention will be described with reference to the drawings. In the drawings, the same components as those of the above-described conventional technology are denoted by the same reference numerals, and the description of the overlapping portions will be omitted.

FIG. 1 is an elevation view showing the entire impeller inspection apparatus, FIG. 2 is a plan view showing the direction of arrow AA in FIG. 1, and FIG. 3 is a plan view showing the direction of arrow BB in FIG. FIG. 4 is a sectional view showing the impeller and its blade, and FIG. 5 is a plan view showing the impeller and its blade.

In FIG. 1, reference numeral 21 denotes an impeller inspection device,
23 is an operation stand, 44 is a pedestal, and 45 is an inspection stand.
The impeller inspection device 21 includes an operation stand 23 and the operation stand
An underwater television camera 25 mounted inside the 23, an up / down drive motor 28 erected on an inspection stand 45 for adjusting the optical axis of the underwater television camera 25 in an up / down position, and a circumferential direction for adjusting a circumferential movement. It has a drive motor 34 and a rotation drive motor 38 for rotating the inspection gantry 45.

Rollers 24 mounted on the impeller 10 and traveling on the upper surface thereof are mounted on the lower surface of the operation stand 23 at four regular intervals via legs 42 on the circumference.

The underwater television camera 25 is attached to an arm 26 which is curved, the arm 26 is vertically driven shaft 27 (hereinafter
The shaft 27 is connected to an up / down drive motor 28 and moves up and down.

The vertical drive motor 28 is a vertical drive watertight container.
Sealed with 29. By rotating the vertical drive motor 28, a lead screw (not shown) is rotated, and the shaft 27 connected to the nut moves up and down.

A pedestal 44 is mounted on the operation pedestal 23, and an inspection pedestal 45 is provided on the pedestal 44. This inspection stand
The holding member 32 is provided on 45. In addition, the operation stand
A fixing base 46 for fixing the rotary drive watertight container 41 facing the pedestal 44 is provided on the base 23.

A rotary drive motor 38 is provided in the rotary drive watertight container 41. On the pedestal 44, a hanging metal fitting 47 having a hanging ear 22 at an upper end portion is provided upright.

Reference numeral 48 in FIG. 1 is a fine adjustment drive mechanism for finely adjusting the vertical drive of the shaft 27. Reference numeral 49 denotes a cylindrical casing into which a transmission mechanism for transmitting vertical drive from the vertical drive motor 28 to the shaft 27 is inserted.

Next, an example of use of the inspection apparatus for an impeller for an internal pump according to the above embodiment will be described. The reactor building has a pool that communicates with the reactor well, and the pool water is used to shield radiation from equipment contained in the pool.

A storage stand for inspecting the internal pump is installed in the pool, and is fixed to the bottom of the pool by anchor bolts.

The impeller inspection device 21 is detachably set on the upper end of the internal pump housed vertically in the storage base. The movement of the impeller inspection device 21 is performed using a suspension lug 22 incorporated in the center of the device main body.

[0038] Below the operation stand 23 of the impeller inspection apparatus 21 more rollers 24 (in this case four places) incorporates <br/> through the legs 42 can rotate freely on the surface of the impeller 10 .

The shaft 27 is moved up and down by an up-down drive motor 28, and the up-down drive motor 28 is driven to rotate, so that the shaft 27 moves up and down. The rotation of the up / down drive motor 28 can be counted by an encoder 30 connected to the motor 28 by a chain 31.

The circumferential movement of the underwater television camera 25 is performed by moving a holding member 32 holding the shaft 27. The movement of the holding member 32 is performed by driving the screw 33 to rotate by the circumferential driving motor 34. The circumferential drive motor 34 is surrounded by a circumferential drive watertight container 35.

The rotation of the circumferential driving motor 34 is controlled by a chain 36.
Can be counted by the encoder 37 connected by. The inspection gantry 45 rotates when the rotation of the rotation drive motor 38 is transmitted to the gear 39. The method of counting the number of rotations is transmitted to the encoder 40 by the gear 39 and counts the number of rotations.

Since the rotary drive motor 38, the encoder 40 and the like are always used in water, the whole is covered with the rotary drive watertight container 41 to prevent water from entering. In addition, impeller
10

Next, the configuration of the underwater television camera 25 will be described. FIG. 6 is a cross-sectional view showing an attached state of the underwater television camera, and FIG. 7 is a plan view showing the direction of arrow CC in FIG.

The underwater television camera 25 shown in FIG. 1 is incorporated in a pair of camera watertight containers 50, 50 and is arranged in parallel. At the upper part of the camera watertight containers 50, 50, a metal mirror 51 (mirror-polished stainless steel surface with a chrome-plated surface) is incorporated at an angle of 45 °. The optical axis of the underwater television camera is directed toward the blade surface of the impeller by reflecting the metal mirror 51.

A plurality of small lamps 52 are arranged in the middle part of the camera watertight containers 50, 50 containing the underwater television cameras, so that they can be illuminated.

Next, the operation of the impeller inspection apparatus configured as described above will be described. First, the operation of the reactor is stopped as in the prior art, and the reactor pressure vessel is filled with water to shield radiation. Then, the lid of the reactor pressure vessel is removed, the reactor well is filled with water, and the reactor internals are removed.

Thereafter, the boss 10a at the upper end of the impeller 10 is gripped in water using an impeller lifting tool (not shown), the impeller and the shaft are lifted together by a hoist, taken out of the reactor pressure vessel, and stored in a predetermined pool. Carry in place.

The you install the impeller inspection device 21 on surface of the impeller 10 in this state. The optical axis of the underwater television camera 25 incorporated in the impeller inspection device is adjusted vertically, the movement in the circumferential direction is adjusted, and the entire inspection device is rotated by underwater remote control. Then, the defect has been inserted an underwater television camera 25 to the blade clearance of the impeller, the image information of the blade surface of the impeller is obtained.

Incidentally, two underwater television cameras 25 are incorporated, and the underwater television camera 25 is provided between the blades of the impeller.
When 25 is inserted, image information can be obtained simultaneously on the front surface of the blade of the impeller and the back surface of the blade of another impeller.

The positioning of the underwater television camera may be operated while viewing the image information from the underwater television camera. However, the coordinates of the target position are automatically determined in advance by position information obtained from a position detector such as an encoder connected to a motor. It is easy to move to.

According to this embodiment, the underwater television camera can be focused in a short time in a narrow place by the complicated shape of the blade of the impeller for the internal pump. Image information can be easily obtained.

This makes it possible to accurately inspect the appearance of the blade surface of the impeller, and to easily detect even a minute scar on the blade surface of the impeller, thereby improving the inspection accuracy and reliability.

By inspecting the blades of the impeller, an imbalance in the rotation of the impeller 10 and the shaft 12 can be detected at an early stage, and the internal pump can be used in a stable flow characteristic state, so that the heat output of the reactor can be stabilized. Can be controlled.

In the above embodiment, an example of inspecting the blade of the impeller has been described. However, the impeller blade of another component, for example, the blade of the diffuser can be inspected in the same manner, and the working efficiency is improved.

In the above description, the image information is obtained by using the underwater television camera. However, the same operation and effect can be obtained by using another photographing device such as a fiberscope camera.

[0056]

According to the present invention, the distance of the blade surface of the impeller can be appropriately adjusted and inspected by the camera.
The focus of the camera can always be maintained accurately, and a clear and stable image can be obtained.

As a result, it is possible to easily inspect fine imperfections or the like generated on the blade surface of the impeller, thereby improving the inspection accuracy and greatly improving the reliability of maintenance of the internal pump and the nuclear reactor.

[Brief description of the drawings]

FIG. 1 is an elevation view showing an embodiment of an inspection device for an impeller for an internal pump according to the present invention.

FIG. 2 is a plan view showing the direction of arrow AA in FIG. 1;

FIG. 3 is a plan view showing the direction of arrow BB in FIG. 1;

FIG. 4 is a sectional view showing an impeller blade part.

FIG. 5 is a plan view showing an impeller blade unit.

FIG. 6 is a sectional view showing an attached state of the underwater television camera.

FIG. 7 is a plan view showing the direction of the arrows CC in FIG. 6;

FIG. 8 is a longitudinal sectional view of the internal pump.

[Explanation of symbols]

1 ... internal pump, 10 ... impeller, 10a ... boss,
12 ... shaft, 14 ... gap, 21 ... impeller inspection device, 22 ...
Hanging ears, 23 ... Operation stand, 24 ... Roller, 25 ... Underwater television camera, 26 ... Arm, 27 ... Shaft, 28 ... Vertical drive motor, 29 ... Vertical drive watertight container, 30 ... Encoder, 31 ... Chain, 32 ... holding member, 33 ... screw, 34 ... circumferential drive motor, 35 ... circumferential drive watertight container, 36 ... chain, 37 ... encoder, 38 ... rotary drive motor, 39 ... gear, 40 ... encoder, 41 ... Watertight container for rotary drive, 42…
Leg, 43… Coupling, 44… Pedestal, 45… Inspection stand, 46…
Fixed stand, 47 ... hanging bracket, 48 ... fine adjustment drive mechanism, 49 ... tubular casing, 50 ... watertight container for camera, 51 ... metal mirror,
52… Small lamp.

Claims (1)

(57) [Claims] 1. An operation mount mounted on an upper surface of an impeller of an internal pump via a roller, a camera movably incorporated in the operation mount, an optical axis adjustment, a vertical position adjustment and a peripheral adjustment of the camera. An inspection device for an impeller for an internal pump, comprising: an inspection gantry provided above the operation gantry having a direction movement adjusting mechanism.