JPH07134195A - Inspecting device for internal pump - Google Patents

Abstract

PURPOSE:To surely perform the part surface inspection of an internal pump within a short time, confirm integrity, and improve the avoilabity of a plant. CONSTITUTION:An operation frame 33 is placed on the upper surface of a diffuser 9 in an internal pump through a wheel 35, and a submersible television camera 22 is movably integrated into the operation frame 33. A vertically driving motor 22 and circumferentially turning driving motor for driving the submersible television camera 22 are provided. An inspecting device 21 is vertically moved, rotated, and circumferentially moved in the state where it sits on the upper surface of the diffuser 9 to inspect the inner surfaces of the diffuser 9, a blade 15, and a stretch tube 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal pump inspection device for inspecting a diffuser, a stretch tube or the like of a refrigerating material recirculation pump (hereinafter referred to as an internal pump) with a built-in nuclear reactor. .

[0002]

2. Description of the Related Art In an improved boiling water reactor, an internal pump in which a pump and a drive motor are integrated in a reactor pressure vessel is adopted. This internal pump forcibly circulates the coolant in the reactor pressure vessel to effectively generate steam, and controls the reactor heat output (generated steam amount) by changing the flow rate of the coolant supplied to the core. ing.

FIG. 4 is a cross-sectional view showing a wet motor type internal pump. The internal pump 1 has a pump portion 3 provided inside a reactor pressure vessel 2 and a motor provided outside the reactor pressure vessel 2. And part 4.
The pump unit 3 is composed of a diffuser 9 fixed inside the reactor pressure vessel 2 and an impeller 10 surrounded by the diffuser 9. Impeller of diffuser 9
A diffuser wear ring 11 is fixed around the 10 side.

As shown in FIGS. 5 and 6, the diffuser 9 has a plurality of blades (8 blades in the figure) 15 arranged circumferentially. This diffuser 9 has a lower diffuser boss 17 placed on a stub tube 19, the diffuser boss 17 engages with the upper end of the stretch tube 18, and the lower end of the stretch tube 18 is casing by a nut (not shown). 5 is fixed to the inner surface of the neck portion.

The motor section 4 comprises a rotor 6 mounted on a shaft 12 in a pump casing 5, and a stator 7 provided so as to face the rotor 6. Rotor 6
A main flange 8 is attached to and sealed at the lower end of the pump casing 5 accommodating the stator 7. The upper end of the pump casing 5 is welded to a stub tube 19 attached to the lower mirror of the reactor pressure vessel 2.

The impeller 10 and the shaft 12 are integrally connected, and the shaft 12 extends to the motor unit 4 and extends to the rotor 6.
Are joined together. Therefore, when the motor unit 4 is in operation, the rotational force of the rotor 6 is transmitted to the shaft 12 and the impeller 10 rotates. By rotating the impeller 10, the reactor pressure vessel 2
The coolant inside is discharged from the diffuser 9 toward the lower side of the core.

A collar portion 13 having a larger outer diameter is provided above the shaft 12. The collar portion 13 functions as a back seat for preventing the coolant from flowing into the pump casing 5 during the periodic inspection of the motor portion 4.

A gap 14 is formed between the rotating impeller 10 and the diffuser wear ring 11 of the fixed diffuser 9.
Is provided. Impeller 10 has shaft 12 and rotor 6
Are positioned by connecting and fixing them, but since the shaft 12 projects above the rotor 6,
If there is a slight imbalance between the two, the impeller 10 may swing and rotate, and the gap 14 may become narrow. Impeller 10
Has a plurality of blades attached to the shaft 12 like an impeller and rotating at high speed.

Similarly, as described above, the blade 5 is attached to the diffuser 9 like an impeller, and the twisted coolant discharged by the rotation of the impeller 10 is passed through the blade 16 of the diffuser 9 and twisted. It is supplied to the core as a rectified flow.

If scratches or the like are generated on the surfaces of the impeller 10 and the blade 16 of the diffuser 9, not only pump performance is adversely affected, but also fragments and the like may be scattered in the reactor pressure vessel 2.

Therefore, conventionally, after operating the internal pump 1 for a certain period of time, the internal pump is removed from the core, the outer surfaces of the impeller 10 and the diffuser 9 and the blade 16 are inspected, and by any chance, the surface of the blade 16 is damaged. If there is, it is repaired and the rotational 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 the radiation. Then, the lid (not shown) of the reactor pressure vessel 2 is removed, the reactor well 41 is also filled with water, and the reactor internals are removed.

Next, the holding bolt 15 at the upper end of the impeller 10 is held in water by using the jig for lifting the impeller, and as shown in FIG.
Are taken out from the inside of the reactor pressure vessel 2 and carried to the pool in the reactor building communicating with the reactor well 40. In FIG. 3, reference numeral 42 is a refueling machine, and 43 is a suspension rope. After removing the impeller 10 and the shaft 12, the blade 16 of the diffuser 9 is observed on a television image using an underwater television camera to inspect for scratches such as contact marks.

[0014]

In order to inspect the surface of the blade 16 and the like of the diffuser 9 by using the underwater television camera, the underwater television camera is hung from the refueling machine 42 at the upper part of the furnace, and the diffuser 9 is suspended. It is necessary to move the underwater TV camera around the blade 16 of.

However, when remotely moving the underwater television camera underwater by remote control, it is very difficult to always keep the distance between the underwater television camera and the blade 16 of the diffuser 9 constant. Further, since the work is performed under the water several tens of meters, it is difficult to operate the underwater lighting device so as not to cast a shadow on the subject of the underwater television camera, and to adjust the brightness. Further, it is difficult to insert the underwater television camera into a narrow gap where one blade of the diffuser 9 and the other blade are curved to work.

Therefore, there is a problem in that a clear image information cannot be obtained by the underwater television camera, and a scar generated on the surface of the blade or the like of the diffuser 9 is missed. The present invention has been made to solve the above-mentioned problems, and includes a diffuser 9 and a stretch tube 18 for a reactor pressure vessel 2
The blade of the diffuser 9 when installed at the bottom inside
An object of the present invention is to provide an inspection device for an internal pump capable of inspecting minute scratches on the surface of 16 with high accuracy and certainty.

[0017]

DISCLOSURE OF THE INVENTION The present invention relates to an operation stand mounted on the upper surface of a diffuser of an internal pump via wheels, an underwater television camera freely mounted on the operation stand, and the underwater television set. The camera is provided with a vertical position adjustment mechanism and a circumferential movement adjustment mechanism for the camera.

[0018]

With the diffuser and stretch tube of the internal pump to be inspected as a unit installed in the reactor pressure vessel, the inspection device in which the underwater television camera is movably incorporated is set at the upper end of the diffuser.

A drive motor for moving the underwater television camera up and down and in the circumferential direction for scanning is previously incorporated in this inspection apparatus. This inspection device is suspended above the diffuser and seated on the diffuser top surface. Insert the underwater television camera between the diffuser blades and set it to the initial position with the turning reference sensor.

A surface of a diffuser blade or 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 image of the underwater television camera is also recorded on the VTR to perform a reliable inspection without inspection failure.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the inspection device for an internal pump according to the present invention will be described with reference to FIGS. In addition,
In the figure, the same components as those of the above-described conventional technique are designated by the same reference numerals, and the description of the overlapping portions will be omitted.

FIG. 1 is an elevational view showing an entire inspection apparatus for an internal pump for inspecting a diffuser and a stretch tube, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a state at the time of periodic inspection of a nuclear reactor. It is sectional drawing shown.

In FIGS. 1 and 2, reference numeral 21 is an inspection device for inspecting the diffuser and the stretch tube, and 33 is a pedestal. A plurality of underwater television cameras 22 are provided inside the inspection device 21, and by operating the drive motor 29, the camera drive roller 26 is rotated and the underwater television camera 22 can be vertically adjusted in position.
The vertical movement of the underwater television camera 22 can be confirmed by the signal of the encoder 30 linked with the camera driving roller 27.

Further, in order to move (turn) the entire inspection device 21 in the circumferential direction, a rotation drive motor 36 is provided inside the inspection device 21.
The wheels 35 installed on the underside of the stand 33
Runs on the upper surface of the diffuser 9 and moves in the circumferential direction. Also in this circumferential movement, the traveling distance can be confirmed by the encoder 30 incorporated on the pedestal 33.

The cable 23 integrated with the underwater television camera 22 is moved up and down by the above-mentioned camera driving roller 26. However, in order to obtain a stable up and down movement of the underwater television camera 22, the cable 23 has a plurality of cable guides 24 and 25. Individually incorporated. Also, the camera drive roller that drives the cable 23 up and down.
A spring 28 is provided between 26 and 27 to secure a proper tension between the rollers.

A plurality of underwater illuminators 38 are incorporated in the periphery of the underwater television camera 22 so that the environment for inspecting the diffuser and the stretch tube is improved and an accurate visual inspection can be performed. Further, an insertion guide 34 is provided below the drive rollers 26 and 27 so that the underwater television camera 22 does not shake during inspection, and serves to prevent the underwater television camera 22 from shaking and protect the underwater television camera 22 when it is stored. It has a structure.

Suspending ears 31 are provided above the inspection device 21 so that the entire inspection device 21 can be lifted. A cylindrical cover 32 is attached around the inspection device 21 to protect the parts.

Next, an example of the inspection of the diffuser and the stretch tube by the inspection device 21 according to the above embodiment is shown in FIG.
A description will be given with reference to FIGS. 1 and 2. First, the inspection device 21 shown in FIG. 1 is suspended in the reactor pressure vessel 1 from the hoist 41 of the refueling machine 42 installed above the reactor pressure vessel 2 using the lifting rope 43. The inspection device 21 hung in the reactor pressure vessel 1 is hung right above the internal pump 1 and is detachably set on the upper surface of the diffuser 9.

A plurality of wheels are provided below the pedestal 33 of the inspection device 21.
35 (4 pieces in this case) are incorporated and the upper end of the diffuser 9 can be freely rotated. In the rotation (turning) drive, the wheel 35 is rotated by rotating the turning drive motor 36. The rotation of the inspection device 21 is determined by the encoder 30 installed on the frame 33.
You can count by. Also mount 33
A swivel reference sensor 37 is incorporated above to obtain a reference (zero point) for the rotation (turning) of the inspection device 21.

In the circumferential movement of the underwater television camera 22, the turning drive motor 36 is driven, and the wheels 35 are rotated by the connecting member 39 to perform the circumferential movement. The swing drive motor 36 is surrounded by a watertight container. The rotation in the circumferential direction can be counted by the encoder 30 incorporated on the pedestal 33.

The shape and structure of the diffuser 9 and its blade are as described in FIGS. 5 and 6. Next, the operation of the inspection device will be described.

First, as in the conventional case, the operation of the reactor is stopped and the reactor pressure vessel is filled with water to shield the radiation.
Then, the lid of the reactor pressure vessel is removed, the reactor well is filled with water, and the reactor internal structure is removed.

After that, using an impeller lifting device (not shown), the holding bolt 15 at the upper end of the impeller 10 is grasped in water, the impeller 10 and the shaft 12 are integrally lifted by a hoist, taken out from the reactor pressure vessel 2, and pooled. Move to the storage location in.

After moving the impeller 10 and the shaft 12, the inspection device 21 is installed on the upper surface of the diffuser in the reactor pressure vessel 2. The optical axis of the underwater television camera 22 incorporated in the inspection device 21 is vertically adjusted, the circumferential movement is adjusted, and the entire inspection device is rotated by underwater remote control. Then, the underwater television camera 22 is inserted into the diffuser blade gap to obtain image information of the diffuser blade surface and the inner surface of the stretch tube.

It should be noted that a plurality of underwater television cameras 22 can be built in, and the underwater television cameras can be installed in the blade gap of the diffuser.
By inserting 22, it is possible to obtain image information of the blade surfaces of a plurality of parts at once.

The positioning of the underwater television camera 22 can be accurately performed by the insertion guide. It is also possible to operate while viewing the image information from the underwater television camera 22. Furthermore, it is also easy to automatically move the coordinates of the target position in advance based on position information obtained from a position detector such as an encoder connected to the motor.

According to the present embodiment, the underwater television camera can be accurately focused in a short time in a narrow place such as the blade surface of the diffuser for an internal pump or the inner surface of the stretch tube in a state where it is installed in the reactor pressure vessel. Therefore, it is possible to easily obtain clear and stable image information that is in focus.

As a result, it becomes possible to accurately inspect the blade surface and the inner surface of the diffuser and the stretch tube, and it is possible to easily detect even minute scratches on the surface of the diffuser blade and the stretch tube, thus improving the inspection accuracy and its reliability. Can be made.

Further, since the inspection with the diffuser and the stretch tube installed can be surely conducted in a short time, the inspection can be conducted promptly without delaying the regular inspection process.

By inspecting the diffuser and the stretch tube, it is possible to detect an imbalance in the rotation of the internal pump in the initial stage, and the internal pump can be used in a stable flow characteristic state, and therefore, the heat output of the reactor and the reactor can be stabilized. Can be controlled.

[0041]

According to the present invention, the inspection device can be seated on the upper surface of the diffuser while the diffuser and the stretch tube are installed in the reactor pressure vessel, so that the appearance of the blade surface of the diffuser and the inner surface of the stretch tube can be accurately inspected. A clear and stable image can be obtained.

As a result, it is possible to easily inspect fine scratches and the like generated on the surface of the diffuser and the stretch tube, and the inspection accuracy is improved, and the reliability of maintenance of the internal pump and the nuclear reactor is significantly improved.

[Brief description of drawings]

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

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

FIG. 3 is a cross-sectional view showing a state at the time of periodic inspection of a nuclear reactor.

FIG. 4 is a vertical cross-sectional view showing an internal pump installed in the nuclear reactor of FIG.

5 is a plan view showing a diffuser blade portion in FIG. 4. FIG.

6 is a vertical cross-sectional view showing the diffuser in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal pump, 2 ... Reactor pressure vessel, 3 ... Pump part, 4 ... Motor part, 9 ... Diffuser, 10 ... Impeller, 21 ... Inspection device, 22 ... Underwater television camera, 23 ... Cable, 24, 25 ... Cable guides, 26, 27 ... Camera drive rollers, 29 ... Drive motors, 30 ... Encoders, 31 ... Hanging ears, 33
... Operation platform, 34 ... Insertion guide, 35 ... Wheels, 36 ... Swiveling drive motor, 37 ... Swing reference sensor, 38 ... Underwater illuminator, 39 ... Connecting member, 40 ... Reactor well, 41 ... Hoist, 42 ... Fuel collecting Replacement machine, 43 ... Hanging rope.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G21C 19/02 K 8908-2G

Claims (4)

[Claims] 1. An operation stand mounted on the upper surface of a diffuser of an internal pump via wheels, an underwater television camera movably incorporated in the operation stand, and a vertical drive mechanism for driving the underwater television camera. An inspection apparatus for an internal pump, comprising: and a circumferential turning drive mechanism. 2. The underwater television camera is attachable to and detachable from a diffuser stretch tube in a state of being suspended from an auxiliary hoist of a refueling machine provided above a reactor pressure vessel and installed at a bottom portion of the reactor pressure vessel. The inspection device for an internal pump according to claim 1, further comprising a guide mechanism capable of inserting the underwater television camera at the position of the diffuser blade. 3. The vertical movement mechanism includes a camera driving roller,
The inspection device for an internal pump according to claim 1, comprising a drive motor for driving the drive roller and a cable guide for guiding a cable connected to the underwater television camera. 4. The internal drive according to claim 1, wherein the circumferential turning drive mechanism comprises a turning reference sensor mounted in a cylindrical cover, and a turning drive motor driven by an instruction from the turning reference sensor. Inspection device for pumps.