JPH11304981A - Support device for inspecting internal pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To directly visually inspect impeller and pump shaft under low radiation environment and easily perform liquid penetrant flaw test, overhaul, washing work, etc. SOLUTION: This support device supports an impeller 20 and a pump shaft 21 connected to this in one during a visual inspection and the like among internal pumps capable of disassembling which are provided in a reactor pressure vessel of a boiling water reactor. A movable shield vessel 32 surrounding whole impeller and a pump shaft upper part is provided. The shield vessel is capable of containing water inside and has a shaft penetration support projectable upward, by penetrating in the lower part of the pump shaft in the state the upper part of the pump shaft is seated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support for an internal pump used for performing a visual inspection or the like in a periodic inspection of an internal pump provided in a reactor pressure vessel of a boiling water reactor. The present invention relates to a device, and more particularly to an inspection support device for an internal pump that can safely support an impeller and a pump shaft that are integrally removed from a furnace in a radiation-shielded state.

[0002]

2. Description of the Related Art A boiling water reactor having an internal pump for circulating reactor water inside a reactor pressure vessel has already been operated and is subject to periodic inspections and the like. A plurality of such internal pumps are provided in an annular portion formed between the core shroud, the shroud support cylinder, and the reactor pressure vessel in a uniform arrangement. The internal pump is roughly configured to include an impeller located inside the reactor pressure vessel, a driving motor unit located outside the reactor pressure vessel, and a pump shaft connecting these components. (Note that an impeller and a pump shaft that are integrally fastened are referred to as an impeller shaft.) The lower part of the pump shaft
It penetrates a RIP nozzle provided in the lower mirror portion of the reactor pressure vessel, is fitted to a motor via a key in a motor casing welded and fixed to the RIP nozzle, and is fastened by a coupling stud.

An external loop circulation system is used for cooling the motor during operation of the internal pump. The cooling water inside the motor is pressurized and driven by an auxiliary impeller directly connected to the motor rotating body, and various parts in the motor are driven. The cooling water is supplied to the heat exchanger via a cooling pipe from a cooling water outlet nozzle attached to the upper part of the motor casing, and after the heat is removed there,
It is configured to return from the cooling water inlet nozzle of the motor casing via the cooling pipe.

[0004] A purge water nozzle is provided above the cooling water outlet nozzle, from which purge water is constantly supplied.
This purge water rises in an annular portion formed by the stretch tube and the pump shaft, and flows into the furnace. This prevents the reactor water and the inner cladding from entering the motor, thereby preventing the motor and the pump shaft from being contaminated by radiation.

[0005] Such internal pumps for boiling water reactors require maintenance of the equipment.
All are designed to be removable. Then, in the periodic inspection of the reactor, after releasing the connection between the impeller shaft and the motor, it was taken out of the reactor pressure vessel with a special remote gripper, moved into the fuel pool, and installed in the fuel pool. They are temporarily placed on a dedicated stand or a dedicated inspection table, and are subjected to indirect visual inspection using an underwater TV camera.

[0006]

The upper part of the impeller shaft of the internal pump is located in the reactor pressure vessel,
Since it comes into contact with the high-speed flow reactor water, it is radioactively contaminated by the adhesion of the inner cladding, so that it is necessary to secure the required shielding water depth in the visual inspection, and it is impossible to lift it into the air.

For this reason, the visual inspection operation is a remote underwater operation, and the inspection of the pump shaft requires a rotation mechanism of the pump shaft and a feed mechanism in the axial direction of the camera. Furthermore, for the inspection of the outer surface of the impeller, the accessibility of the underwater camera is extremely poor, a complicated mechanism is required as the inspection equipment, all the equipments are expensive, and the inspection work requires a lot of labor. .

[0008] In order to further improve the inspection accuracy, a penetrant inspection test or the like is required. However, it is practically impossible to perform a penetrant inspection test in water while securing the shielding water depth. Further, a pump shaft is integrally connected to the impeller, but since the upper portion of the pump shaft is located near the impeller, it is in a radiation contamination state. On the other hand, since the lower part of the pump shaft is kept in contact with the reactor water by the purge water as described above, the lower part of the pump shaft is in a state where visual observation with the naked eye is possible. But,
Also in the lower part of the pump shaft, the impeller connected to the upper end is in a contaminated state, so that it has not been easy to perform a visual observation with the naked eye conventionally. And
Even when such impellers and pump shafts need to be cleaned, the accessibility to the target location is poor, making cleaning extremely difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the problem of such an internal pump, particularly for inspection of an impeller and a pump shaft, and an object thereof is to provide an impeller and a pump shaft under a low radiation environment. , Can be directly visually inspected,
It is an object of the present invention to provide an internal pump inspection support device that can easily perform a penetrant inspection, a disassembly inspection, and a cleaning operation.

[0010]

In order to achieve the above-mentioned object, according to the first aspect of the present invention, an impeller and a decomposable internal pump provided in a reactor pressure vessel of a boiling water reactor are provided. An inspection support device for an internal pump that integrally supports a pump shaft connected thereto during a visual inspection or the like, and includes a portable shielding container that surrounds the entire impeller and an upper portion of the pump shaft. The shielding container is configured to be capable of storing water therein and having a shaft penetration supporting portion that can penetrate a lower portion of the pump shaft and project outward when the upper portion of the pump shaft is seated. An inspection support device for an internal pump is provided.

[0011] According to the present invention, radiation is blocked by covering the impeller, which is radioactively contaminated, of the impeller shaft and the upper part of the pump shaft with the shielding container, so that the lower part of the pump shaft can be moved in the air. It can be possible, thereby enabling visual observation with the naked eye.

According to a second aspect of the present invention, in the inspection support apparatus for an internal pump according to the first aspect, the shaft penetrating support portion has a seal member for water sealing at a portion that penetrates and supports the pump shaft. An inspection support device for an internal pump is provided.

According to the present invention, since the sealing member for water sealing is provided on the through-support portion through which the pump shaft of the shielding container penetrates, it is possible to reliably hold the water containing water in the shielding container. Becomes

According to a third aspect of the present invention, in the inspection support apparatus for an internal pump according to the first or second aspect, the shielding container has a liftable lid which can be opened and closed. Provided is a support device for inspection of an internal pump, characterized in that a hanger that can be connected to the internal pump is provided.

According to the present invention, the installation of the hanging lid and the hanging jig above the shielding container enables the impeller shaft to be lifted by the ceiling crane in the reactor, and the necessary movement can be easily performed.

According to a fourth aspect of the present invention, in the inspection support device for an internal pump according to any one of the first to third aspects, a water supply pipe and a drainage pipe are connected to the shielding container, and the water supply pipe and the drainage pipe are connected to the shielding vessel. A closed loop is formed by piping, and a detergent supply unit for supplying a chemical decontamination detergent and a circulation pump for circulating the detergent are connected to the loop piping, and an impeller of an internal pump housed in the shielding container and An inspection support device for an internal pump, wherein an upper part of a pump shaft can be chemically decontaminated.

According to the present invention, the activated impeller and the upper part of the pump shaft can be easily cleaned by chemical decontamination, and the entire impeller shaft including the impeller blade surface can be exposed to the air. Becomes

According to a fifth aspect of the present invention, in the inspection support apparatus for an internal pump according to any one of the first to third aspects, the shielding container has an ultrasonic cleaning facility. An inspection support device is provided.

According to the present invention, the ultrasonic cleaning device is mounted in the shielding container, and the cleaning operation centering on the impeller blade surface can be performed.

According to a sixth aspect of the present invention, in the inspection support device for an internal pump according to the fourth or fifth aspect, the shielding container is configured to be capable of housing a diffuser of the internal pump. An inspection support device is provided.

According to the present invention, the shielding container has a structure in which the diffuser can be installed, and the decontamination of the diffuser is performed.
It becomes possible to take it out into the air, and it becomes possible to carry out cleaning work centering on the diffuser blade surface.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1 to 5 show a configuration of an inspection support device for an internal pump, and FIGS. 6 and 7 show configurations of a reactor pressure vessel and an internal pump.

First, the structure of the reactor pressure vessel and the internal pump will be described with reference to FIGS.

As shown in FIG. 6, the fuel 1 loaded in the core of the reactor pressure vessel has a lower end supported by a core support plate 2 and an upper portion supported by an upper lattice plate 3. The core support plate 2 and the upper lattice plate 3 are fixed to a cylindrical core shroud 4. The core shroud 4 is welded and fixed to the lower mirror portion 8 of the reactor pressure vessel 7 via a shroud support leg 5 and a cylindrical shroud support cylinder 6. Further, a shroud head 11 having a stand pipe 9 and a steam separator 10 is installed above the shroud sapoleg 5, and a steam dryer 12 is further installed above.

On the other hand, an annular portion formed by the core shroud 4, the shroud support cylinder 6, and the reactor pressure vessel 7 is partitioned by a shroud support plate 13 below the reactor pressure vessel 7, and the shroud support plate 13 is It is fixed to the cylinder 6 and the reactor pressure vessel 7 by welding. Then, the internal pump 14 is uniformly arranged in the circumferential direction in the above-described annular portion.

FIG. 7 shows the configuration of the internal pump 14 in detail. As shown in FIG. 7, the internal pump 14 has a diffuser 15 at an upper end. The diffuser 15 penetrates the shroud support plate 13, is installed on a RIP nozzle 16 provided in the lower mirror section 8, and stretches. It is mechanically fastened by a tube 17 and a nut 18.

An impeller shaft 22 having an impeller 20 and an impeller 20 and a pump shaft 21 fastened to each other by a body, penetrates the RIP nozzle 16 and
The motor 24 is fitted to the motor 24 by a key 25 in a motor casing 23 welded and fixed to the nozzle 16 and fastened by a coupling stud 26.

Motor 2 during operation of internal pump 14
The cooling method of No. 4 employs an external loop circulation method, in which the cooling water inside the motor is pressurized and driven by an auxiliary impeller 28 directly connected to the motor rotating body 27, circulates through various parts in the motor, and the motor casing 23 The cooling water is supplied to a heat exchanger (not shown) through a cooling pipe (not shown) from a cooling water outlet nozzle 29 attached to the upper portion, and after the heat is removed there, the cooling water is passed through a cooling pipe (not shown). It is configured to return from the cooling water inlet nozzle 30 of the motor casing 23.

On the other hand, purge water is always supplied from a purge water nozzle 31 provided above the cooling water outlet nozzle 29,
This purge water rises in an annular portion formed by the stretch tube 17 and the pump shaft 21 and flows into the furnace. This prevents the reactor water and the inner clad from entering the motor 24 and prevents the motor 24 and the pump shaft 21 from being contaminated by radiation.

Incidentally, such an internal pump 14 is designed to be entirely removable from the necessity of maintenance of the equipment. In this case, the impeller shaft 22 is used for the motor 2 during the periodic inspection of the reactor.
After releasing the connection with the reactor 4, it can be removed from the reactor pressure vessel 7 by a special remote gripper.

Next, an inspection support device for an internal pump according to the present embodiment will be described with reference to FIGS.

As shown in FIG. 1, the inspection support device of the internal pump according to the present embodiment has a shielding container 32. The shielding container 32 is detachably mounted on a gantry 33 installed at the bottom of the fuel pool 45, and has a configuration in which an upper surface is opened. That is, the shielding container 32 has a cylindrical shape with a bottom as a whole, has a through hole 34 formed in the center of the bottom wall, and has a receiving stand 35 which stands up in an arrangement surrounding the through hole 34. I have. At the upper end of the outer surface, a fastener including a swing bolt 38 and a nut 39 for attaching and detaching a hanging lid described later is provided. The through hole 34 has a diameter that can penetrate the lower part of the pump shaft 21, and the upper end of the through portion 34 has
A large-diameter step portion on which the upper part of the pump shaft 21 can be seated is formed, thereby forming a receiving base 35.

FIG. 2 shows a configuration in which the receiving base 35 of the shielding container 32 is enlarged. As shown in FIG. 2, on the upper inner peripheral surface of the step portion of the receiving table 35, a seal member 40 for water sealing is installed, for example, up and down, two steps, through concave grooves. . These seal members 40 are, for example, rubber rings, and the inner peripheral surfaces of these seal members 40 can be in close contact with the outer peripheral surface of the pump shaft 21. As a result, the water contained in the shielding container 32 is prevented from leaking downward, and the water shielding effect can be obtained safely even when the shielding container 32 is drawn out into the air as described later. The weight and size of the container 32 can be reduced.

At the time of inspection, the internal pump 1
The impeller shaft 22 removed from the reactor pressure vessel 7 due to the disassembly of the reactor 4, that is, the impeller 20 and the pump shaft 21 are transferred into the fuel pool 45 and suspended from above the shielding vessel 32, and the pump shaft 21 penetrates. The upper part of the pump shaft 21 is seated on the receiving stand 35 while being inserted through the hole 34. As a result, the entire impeller 20 and the upper part of the pump shaft 21 are radioactively contaminated and are covered with the shielding container 32.
Radiation is blocked to the outside of the device.

FIG. 3 shows a configuration in which the shielding container 32 is in the closed state, a lifting configuration thereof, and their operations.
That is, as shown in FIG. 3, the shielding container 32 has a hanging lid 37 that opens and closes the upper surface, and the hanging lid 37 is detachably attached to the upper end of the shielding container 32 by a swing bolt 38 and a nut 39. It has become. A hook portion 37a is provided on the upper surface of the suspension lid 37, and the hook portion 37a has a hook 3 at the lower end of a wire 36a of the hanging tool 36.
6b can be hooked. The suspension fishing 36 can be lifted by hooks 46 of wires (not shown) of an overhead crane in a nuclear reactor.

With such a configuration, the impeller 20 of the internal pump is completely shielded and
2 and the lower part of the pump shaft 21
4 and is projected outside the shielding container 32.

Therefore, if the shield vessel 32 is pulled up above the fuel pool 45 by the action of a ceiling crane (not shown) in the reactor, the shield vessel 32 is lifted up from the gantry 33 together with the impeller 20 and the pump shaft 21 and lifted into the air. 4, after draining in this state, a visual inspection of the outer surface of the pump shaft 21 beside the fuel pool 45 can be performed.

Also, if necessary, the fuel pool floor 47
By installing the shielding container 32 on a stand (not shown) provided above, a detailed visual inspection or a penetrant inspection can be performed. Further, a key 25 provided at an intermediate portion of the pump shaft 21 and a coupling stud 2 at the lower end are provided.
6 can be disassembled, inspected, and parts replaced.

FIG. 5 shows an application example in which equipment for chemical decontamination is added. As shown in FIG. 5, in the present configuration example, the shielding container 32 is installed on the gantry 41, and the shielding container 32
Are connected to a water supply pipe 42 and a drain pipe 43, and the water supply pipe 42 and the drain pipe 43 form a closed loop. Then, a detergent supply unit 44a for supplying a detergent for chemical decontamination and a circulation pump 44b for circulating the detergent are connected to the loop pipe, and the shielding container 3
2 of the internal pump 14 housed in the internal pump 2
0 and the upper part of the pump shaft 21 can be chemically decontaminated.

According to such a configuration, the activated impeller 20 and the upper part of the pump shaft 21 can be easily cleaned by chemical decontamination, and thereafter, the entire impeller shaft including the impeller blade surface is cleaned. It can be taken out of the air and a visual inspection or a penetrant inspection can be directly performed on the entire surface including the impeller 20. Further, when decontamination is performed with such an apparatus, the impeller shaft 2
2, disassembly, inspection of fastening parts, replacement of parts, etc. are also possible.

Further, although not shown, in the present embodiment, an ultrasonic cleaning facility is provided inside the shielding container 32 so that the wing surface of the impeller 20 and the like can be removed from the cladding adhered during operation. It is also possible.

Furthermore, by making the structure of the shielding container 32 a structure in which the diffuser 15 can be stored, it is possible to perform cleaning, decontamination, and take-out of the diffuser 15 into the air.

According to the above embodiment, in the periodic inspection of the internal pump for supplying the reactor coolant to the reactor core, the impeller shaft 22 removed from the inside of the reactor is integrally handled, and the pump shaft is operated under a low radiation environment. 21 A direct visual inspection and a penetrant inspection of the outer surface can be easily performed. The key 25 and the coupling stud 26
Inspection and replacement of parts.

Further, the clad removal or decontamination of the impeller shaft 22 can be performed by the combined use of ultrasonic cleaning or chemical decontamination. Inspection of the diffuser can be easily performed.

[0045]

As described above, according to the present invention, the impeller shaft detached from the reactor pressure vessel is integrated with the internal pump during the periodic inspection of the internal pump for supplying the reactor coolant to the reactor core. Direct visual inspection and penetrant inspection of the outer surface of the pump shaft can be easily performed under handling and low radiation environment. In addition, the key and the coupling stud can be disassembled and inspected, and parts can be replaced. Furthermore, by using ultrasonic cleaning or chemical decontamination together, it is possible to remove or decontaminate the impeller shaft cladding.
Penetration inspection and disassembly of impeller shaft fastening parts can also be performed. Furthermore, by performing decontamination or the like on the diffuser, it is also possible to perform an inspection of the diffuser.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a support device for inspection of an internal pump according to the present invention.

FIG. 2 is a partially enlarged view of the apparatus of FIG. 1;

FIG. 3 is a view showing an example of an inspection method according to the embodiment.

FIG. 4 is a view showing an example of a water sealing method according to the embodiment.

FIG. 5 is a diagram showing an example of a decontamination method using the inspection support device according to the embodiment.

FIG. 6 is an overall configuration diagram of a reactor pressure vessel having an internal pump.

FIG. 7 is an enlarged sectional view of the internal pump shown in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel 2 Core support plate 3 Upper lattice plate 3 Core shroud 5 Shroud support leg 6 Shroud support cylinder 7 Reactor pressure vessel 8 Lower mirror part 9 Stand pipe 10 Steam separator 11 Shroud head 12 Steam dryer 13 Shroud support plate 14 Internal pump 15 Diffuser 16 RIP nozzle 17 Stretch tube 18 Nut 19 Impeller pad 20 Impeller 21 Pump shaft 22 Impeller shaft 23 Motor casing 24 Motor 25 Key 26 Coupling stud 27 Motor rotating body 28 Auxiliary impeller 29 Cooling water outlet nozzle 30 Cooling water Inlet nozzle 31 Purge water nozzle 32 Shielding container 33 Frame 34 Through hole 35 Cradle 36 Hanging tool 36a Wire 37 Hanging lid 37a Hook 38 Swingbo Lt 39 nut 40 seal member 41 gantry 42 water supply pipe 43 drainage pipe 44a detergent supply section 44b circulation pump 45 fuel pool 46 hook

Claims (6)

[Claims] A disassembled internal pump provided in a reactor pressure vessel of a boiling water reactor, wherein an impeller and a pump shaft connected to the impeller are integrally supported during a visual inspection or the like. An inspection support device for a null pump, comprising a portable shielding container surrounding the entirety of the impeller and an upper portion of the pump shaft, and the shielding container can accommodate water therein and has an upper portion of the pump shaft. An inspection support device for an internal pump, characterized in that it has a shaft penetration support portion which can penetrate a lower portion of the pump shaft and project outward when seated. 2. The internal pump inspection support device according to claim 1, wherein the shaft penetrating support portion has a seal member for water sealing at a portion that penetrates and supports the pump shaft. Inspection support device for pumps. 3. The inspection support device for an internal pump according to claim 1, wherein the shielding container has an openable and closable suspension lid, and a suspension which can be connected to a ceiling crane in a nuclear reactor above the suspension lid. An inspection support device for an internal pump, wherein a tool is provided. 4. The inspection support device for an internal pump according to claim 1, wherein a water supply pipe and a drain pipe are connected to the shielding container, and a closed loop is formed by the water supply pipe and the drain pipe. And
And a detergent supply unit for supplying a detergent for chemical decontamination to the loop pipe and a circulation pump for circulating the detergent are connected, and the impeller and the pump shaft of the internal pump housed in the shielding container are chemically decontaminated. An inspection support device for an internal pump, which is made possible. 5. The supporting device for inspection of an internal pump according to claim 1, wherein the shielding container has a facility for ultrasonic cleaning. . 6. The inspection support device for an internal pump according to claim 4, wherein the shielding container is configured to be able to store a diffuser of the internal pump. .