JP3626219B2 - Internal pump casing closing device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an internal pump casing closing device for closing a motor casing when disassembling and inspecting a pump portion of an internal pump incorporated in a boiling water reactor.
[0002]
[Prior art]
For example, the boiling water reactor is configured as shown in the longitudinal sectional view around the reactor pressure vessel in FIG. That is, a reactor well 5 on a cylinder is formed between an operating floor 2 provided above a reactor pressure vessel (hereinafter referred to as RPV) 1 and an RPV 1, and a spent fuel pool 3 and equipment are formed on the left and right sides thereof. A storage pool 4 is provided.
[0003]
The RPV 1 is supported by a support 6, and a cylindrical shroud 7 is disposed in the RPV 1 so as to surround the core 17, and a shroud head 8 is placed on the upper part. An upper part of the shroud head 8 is provided with a steam separator 9 for separating only vapor in the gas phase from the gas-liquid two-phase flow generated by the boiling of the coolant in the reactor core 17, and further above the steam from the steam. A steam dryer 10 for removing the components is provided.
[0004]
In addition, a plurality of internal pumps 11 are penetrating and penetrating into the RPV 1 at the bottom of the RPV 1. For example, ten internal pumps 11 are annularly arranged in the annular space 16 formed by the outer peripheral surface of the shroud 7 and the inner peripheral surface of the RPV 1 at equal pitch intervals in the circumferential direction. The coolant supplied from the water supply nozzle 18 is sucked from the environmental space 16 and led to the core 17 in the shroud 7.
[0005]
On the other hand, during the periodic inspection of the nuclear reactor, the nuclear containment vessel top cover 35, RPV top cover 19, steam dryer 10, steam separator 9 and shroud head 8 are installed in the equipment storage pool 4, and the fuel constituting the core 17 from the RPV 1. (Not shown) is removed for refueling. For this refueling operation, a refueling machine 12 straddling a reactor well 5 provided on the operating floor 2 is usually used. The refueling machine 12 is equipped with a trolley 13 that traverses the refueling machine 12, and the trolley 13 is equipped with a hoisting machine 15 that winds a suspension rope 14.
[0006]
Next, the internal pump 11 is composed of a pump part 20 and a motor part 21 as shown in the longitudinal sectional view of FIG. 4, and a motor casing 23 is inserted into an opening sleeve 22 protruding from the bottom of the RPV 1. And the upper end part is welded to the opening sleeve 22, and the lower half part of the motor casing 23 is hung outside the RPV1.
[0007]
In the motor casing 23, a motor shaft 24 and a hollow pump shaft 25, which are keyed so as to be separable in the vertical direction, are coaxially accommodated rotatably.
[0008]
An impeller 26 is attached to the upper end portion of the pump shaft 25. A diffuser 27 for diffusing the flow of the coolant is disposed on the outer periphery of the impeller 26. Further, the lower end portion of the diffuser 27 is engaged with the upper end portion of the stretch tube 28, and the diffuser 27 is fixed on the opening sleeve 22 by the stretch tube 28 engaging with the stretch tube nut 29.
[0009]
On the other hand, the motor unit 21 includes a rotor 30 fixed to the outer periphery of the motor shaft 24, a stator 31 disposed on the outer periphery thereof with a predetermined gap, and the like, and a motor casing welded to the lower portion of the RPV 1 23. A motor cover 32 having an auxiliary cover 41 is fastened and fixed to the lower end of the motor casing 23 by stud bolts 36 and nuts 37 to keep the inside of the motor casing 23 liquid-tight. Further, a secondary seal 44 is disposed in the upper part of the motor casing 23, and a secondary seal pressure line 60 is connected to the secondary seal 44.
[0010]
The pump unit 20 and the motor unit 21 are fastened and fixed to the thrust disk 34 of the motor unit 21 by a coupling stud 33 and a coupling stud nut 42 attached to the lower end of the motor shaft 24.
[0011]
The internal pump 11 configured as described above is disassembled at the time of periodic inspection of the nuclear reactor, and each part is inspected and repaired. This disassembly will be described with reference to FIG. 4 and FIG.
[0012]
First, the nut 37 is loosened, and the motor unit 21, the impeller 26, the pump shaft 25, and the motor shaft 24 are slightly lowered so that the lower surface of the impeller 26 and the upper surface of the stretch tube 28 are brought into close contact to form a primary seal. Next, the secondary seal 44 is pressurized by the secondary seal pressurizing line 60 to prevent the reactor water from flowing into the motor casing 23. Then, the reactor water staying in the motor casing 23 is drained, and then the auxiliary cover 41 is removed from the motor cover 32. Then, the coupling stud nut 42 is removed from the coupling stud 33, and then the motor unit 21 is removed from below the motor casing 23. At this time, since the reactor water in the RPV 1 is closed by the primary seal and the secondary seal 44, the reactor water does not leak from the lower part of the motor casing 23 to the outside of the system.
[0013]
Next, an internal pump lower closing flange (hereinafter referred to as a lower closing flange) 43 is attached to the motor casing 23 from below, and water is poured into the motor casing 23. Thereafter, the secondary seal 44 is released. At this time, the water poured into the motor casing 23 does not leak through the lower closing flange 43.
[0014]
On the other hand, the impeller 26, the pump shaft 25, and the motor shaft 24 are simultaneously taken out from above the RPV 1. In this state, since the reactor water enters the motor casing 23 through the inside of the stretch tube 28, the reactor plug in the RPV 1 is closed by attaching the upper plug 58 to the inner surface of the upper end portion of the stretch tube 28. The upper plug 58 is attached by using the hoisting machine 15 from above the fuel changer 12.
[0015]
When the upper plug 58 is attached, the reactor water in the RPV 1 does not enter the motor casing 23, so the water injected into the motor casing 23 is drained and the lower closing flange 43 is removed. Therefore, finally, the secondary seal 44 is removed from below the motor casing 23. In addition, after completion | finish of inspection, the internal pump 11 is attached in the reverse procedure to the above.
[0016]
By the way, the method of removing the lower closing flange 43 that closes the motor casing 23 is that the water in the motor casing 23 is completely drained by the operator using a flow glass (not shown) of a drain line (not shown). It is designed to be removed after confirmation.
[0017]
In addition, the upper plug 58 is pulled out after the secondary seal 44 and the lower closing flange 43 are attached and water is injected again into the motor casing 23 in the installation of the internal pump 11 performed in the reverse procedure described above.
[0018]
[Problems to be solved by the invention]
In the above-described conventional lower closing flange 43, when the lower closing flange is removed before the drainage in the motor casing 23 is completely performed by an operator's erroneous operation, the water injected into the motor casing leaks, Decontamination work is required. Therefore, there is a possibility that the exposure and regular inspection period of workers working under the internal pump 11 will be long.
[0019]
Further, even when the upper plug 58 is pulled out by mistake during removal or attachment of the lower closing flange 43, the reactor water flows from the inside of the stretch tube 28 and is discharged from the bottom of the motor casing 23. Decontamination work is required. Therefore, similarly, there is a possibility that the exposure and regular inspection period of workers working under the internal pump 11 will be prolonged.
[0020]
SUMMARY OF THE INVENTION The present invention has been made in response to the conventional situation, and its purpose is to prevent the lower closing flange from being removed unless the contaminated water in the motor casing is drained, and to prevent the contaminated water from being erroneously operated by an operator. Is intended to prevent the diffusion of Further, if water is not poured into the motor casing, the upper plug cannot be pulled out, and similarly, the diffusion of contaminated water due to an erroneous operation by an operator is prevented.
[0021]
[Means for Solving the Problems]
To achieve the above object, the present invention detects an amount of water in a motor casing in an internal pump casing closing device that closes a motor casing that is suspended at the bottom of a reactor pressure vessel and houses an internal pump during periodic inspection. A lower closing flange that has a detection means for generating a detection signal and closes the lower portion of the motor casing, and when the detection signal generated from the detection means when the lower closing flange is removed is greater than a predetermined amount of water Is a control panel having an interlock that does not generate a start signal, and an attachment / detachment device that is operated by the start signal generated from the control panel and attaches and detaches the lower closing flange to the lower part of the motor casing
The control panel having an interlock that does not generate a start signal when the detection signal generated from the detection means when the upper plug is removed is equal to or less than a predetermined amount of water, and the motor operated by the start signal generated from the control panel Provided is an internal pump casing closing device including an upper plug handling device for attaching and detaching an upper plug from an upper portion of the casing.
[0026]
[Action]
In the internal pump casing closing device having the above configuration, the amount of water present in the motor casing can be detected by the detecting means provided on the lower closing flange. Further, when the amount of water is greater than a predetermined amount, an interlock is applied, and the lower closing flange attaching / detaching device and the upper plug handling device for attaching / detaching the upper plug do not operate. Therefore, it is possible to prevent the lower closing flange and the upper plug from being removed due to malfunction.
[0030]
【Example】
Hereinafter, an internal pump casing closing device according to the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of a first embodiment of an internal pump casing closing device according to the present invention. The internal pump casing closing device has a lower closing flange 43 provided with a water load sensor 50 for detecting a static load of water. The lower closing flange 43 is disposed on a lifter carriage 51 that moves up and down to the motor casing 23. Cables 48, 49 are connected to the water load sensor 50 and the lifter carriage 51, and the other ends of the cables 48, 49 are controlled with an interlock to the lifter carriage 51 based on information from the water load sensor 50. It is connected to the panel 52. The control panel 52 is connected to a fuel exchanger control panel 56 by a cable 47, and the fuel exchanger control panel 56 is connected to a hoisting machine.
[0031]
In the internal pump casing closing device configured as described above, water in the motor casing 23 is detected by the water load sensor 50, and the detection signal is always sent to the control panel 52 via the cable 48. When a load greater than a predetermined value due to water is detected in the motor casing 23, the lifter carriage 51 that raises and lowers the lower closing flange 43 by the interlock in the control panel 52 cannot be operated. Further, when the water in the motor casing 23 is drained and becomes a predetermined load or less, the interlock in the control panel 52 is released by the detection signal, and the lifter carriage 51 can be operated. Further, during this operation, the water level can be confirmed at any time on the display panel 59 provided in the control panel 52.
[0032]
The detection signal from the water load sensor 50 in the motor casing 23 is also sent from the control panel 52 to the fuel exchanger control panel 56 via the cable 47. If the detection signal does not exceed a predetermined load, the hoisting machine An interlock is built to prevent the upper plug from being pulled out.
[0033]
FIG. 2 shows a configuration diagram of a second embodiment of the internal pump casing closing device according to the present invention. In FIG. 2, the lower closing flange 43 includes a water level sensor 57 for detecting a water level and a transmitter 53 for transmitting a signal to a receiver 55 connected to a reception cable 54 attached to an inner wall surrounding the internal pump. Yes. The lower closing flange 43 is handled by a lifter carriage 51 that moves up and down to the motor casing 23. The receiver 55 and the lifter carriage 51 are connected to the control board 52 by cables 49 and 54, and the control board 52 is configured to control the interlock to the lifter carriage 51 based on the information signal from the water level sensor 57. Yes. Further, the control panel 52 is connected to a fuel exchanger control panel 56 by a cable 47, and this fuel exchanger control panel 56 is connected to a hoisting machine.
[0034]
In the above configuration, water in the motor casing 23 is detected by the water level sensor 57, and the signal is received from the transmitter 53 built in the lower closing flange 43 and stretched around the inner wall surrounding the internal pump 11. 54 is sent to a receiver 55 connected to 54 and always reaches the control panel 52. Other operations such as interlock operation and release are the same as those in the first embodiment.
[0035]
Therefore, according to the present invention, it is impossible to remove the lower closing flange before the water in the motor casing is drained due to an erroneous operation by an operator, and the diffusion of contaminated water in the motor casing is prevented. Therefore, the decontamination work by the contaminated water is unnecessary, so that the exposure of workers can be reduced and the delay of the regular inspection period can be prevented.
[0036]
Also, when water is not poured into the motor casing when the internal pump is installed, the upper plug cannot be removed, preventing the diffusion of contaminated water due to the operator's erroneous operation. Therefore, the decontamination work by the contaminated water is unnecessary, so that the exposure of workers can be reduced and the regular inspection period can be shortened.
[0037]
【The invention's effect】
As described above, in the internal pump casing closing device according to the present invention, in the case where the interlock for removing the lower closing flange is assembled, the operation of removing the lower closing flange is performed before the motor casing is drained. It is not possible to prevent the water in the motor casing from diffusing due to the operator's erroneous operation.
[0038]
Also, in the case where the interlock for pulling out the upper plug is assembled, the upper plug cannot be pulled out unless water is poured into the motor casing, and the water in the motor casing due to the operator's erroneous operation due to the operator's erroneous operation. Diffusion can be prevented.
Therefore, the decontamination work by the contaminated water is unnecessary, so that the exposure of workers can be reduced and the delay of the regular inspection period can be prevented.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a first embodiment of an internal pump casing closing device according to the present invention.
FIG. 2 is a configuration diagram showing a second embodiment of the internal pump casing closing device according to the present invention.
FIG. 3 is a longitudinal sectional view around the reactor pressure vessel.
FIG. 4 is a longitudinal sectional view of an internal pump.
FIG. 5 is an explanatory diagram of an internal pump disassembly procedure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel 2 ... Operating floor 3 ... Spent fuel pool 4 ... Equipment storage pool 5 ... Reactor well 6 ... Support 7 ... Shroud 8 ... Shroud head 9 ... Steam separator 10 ... Steam dryer 11 ... Inter Null pump 12 ... Fuel changer 13 ... Trolley 14 ... Suspension rope 15 ... Hoisting machine 16 ... Annular space 17 ... Core 18 ... Water supply nozzle 19 ... Reactor pressure vessel upper lid 20 ... Pump part 21 ... Motor part 22 ... Opening sleeve 23 Motor casing 24 ... Motor shaft 25 ... Pump shaft 26 ... Impeller 27 ... Diffuser 28 ... Stretch tube 29 ... Stretch tube nut 30 ... Rotor 31 ... Stator 32 ... Motor cover 33 ... Coupling stud 34 ... Thrust disk 35 ... Reactor storage Container top cover 36 ... Stud bolt 37 Nut 41 ... Auxiliary cover 42 ... Coupling stud nut 43 ... Lower closing flange 44 ... Secondary seal 47 ... Cable 48 ... Cable 49 ... Cable 50 ... Water load sensor 51 ... Lifter carriage 52 ... Control panel 53 ... Transmitter 54 ... Reception Cable 55 ... Receiver 56 ... Control panel for fuel changer 57 ... Water level sensor 58 ... Upper plug 59 ... Display panel 60 ... Secondary seal pressure line

Claims (1)

In an internal pump casing closing device that closes a motor casing that is suspended from the bottom of a reactor pressure vessel and houses an internal pump, during periodic inspection, has a detection means for generating a detection signal for detecting the amount of water in the motor casing. A lower closing flange for closing the lower portion of the motor casing, and an interlock that receives a detection signal generated from the detection means when the lower closing flange is removed and does not generate a start signal when a predetermined amount of water is exceeded. A control panel, and an attachment / detachment device that is actuated by a start signal generated from the control panel and attaches / detaches the lower closing flange to the lower part of the motor casing;
The control panel having an interlock that does not generate a start signal when the detection signal generated from the detection means when the upper plug is removed is equal to or less than a predetermined amount of water, and the motor operated by the start signal generated from the control panel An internal pump casing closing device comprising an upper plug handling device for attaching and detaching the upper plug from the upper part of the casing.

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