JPH0763877A - Internal pump casing stopper - Google Patents

Abstract

PURPOSE:To provide an internal pump casing stopper to prevent the diffusion of contaminated water due to the operational error by workers by preventing a lower stopper flange from being dismantled unless contaminated water in a motor casing is drained off. CONSTITUTION:This device consists of a lower stopper flange 43 with a detecting means 50 to give detecting signals corresponding with the water level in a motor casing 23 by detecting it, a control panel 52 with an interlock to prevent a starting signal by receiving detecting signals from the detecting means 50 if a water level is higher than a specified one and a device 51, which works by starting signals from the control panel 52, for attaching the lower stopper flange 43 to the lower part of a motor casing 23 or detaching the flange from it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal pump casing closing device for closing a motor casing when disassembling and checking a pump portion of an internal pump incorporated in a boiling water reactor.

[0002]

2. Description of the Related Art For example, a boiling water reactor is constructed as shown in a vertical sectional view of the periphery of a reactor pressure vessel in FIG. That is, reactor pressure vessel (hereinafter referred to as RPV)
1, an operating floor 2 provided above R,
A cylindrical reactor well 5 is formed between the PVs 1, and a spent fuel pool 3 and an equipment storage pool 4 are arranged on the left and right sides thereof.

The RPV 1 is supported by a support 6,
A cylindrical shroud 7 is disposed in the RPV 1 so as to surround the core 17, and a shroud head 8 is provided above the shroud 7.
Is placed. Above the shroud head 8 is provided a steam separator 9 for separating only vapor in the vapor phase from the vapor-liquid two-phase flow generated by boiling of the coolant in the core 17, and above the shroud head 8 above the shroud head 8. A steam dryer 10 for removing the components is provided.

Further, a plurality of internal pumps 11 are vertically provided at the bottom of the RPV 1 so as to penetrate into the RPV 1. These internal pumps 11 have an annular space 16 formed by the outer peripheral surface of the shroud 7 and the inner peripheral surface of the RPV 1.
In addition, for example, 10 units are annularly arranged at equal pitch intervals in the circumferential direction. Then, the coolant supplied from the water supply nozzle 18 is sucked from the environment space 16 and guided to the core 17 in the shroud 7.

On the other hand, at the time of periodic inspection of the nuclear reactor, the nuclear containment vessel upper lid 35, the RPV upper lid 19, the steam dryer 10, the steam separator 9 and the shroud head 8 are installed in the equipment storage pool 4.
The fuel (not shown) that constitutes the core 17 is taken out from the RPV 1 for refueling. For this refueling work, a refueling machine 12 is usually used which is installed over the reactor well 5 provided on the operating floor 2. A trolley 13 that traverses the fuel exchanger 12 is mounted on the fuel exchanger 12, and a hoisting machine 15 that winds a suspension rope 14 is mounted on the trolley 13.

The internal pump 11 is composed of a pump portion 20 and a motor portion 21 as shown in the longitudinal sectional view of FIG. 4, and the motor casing is provided in an opening sleeve 22 projecting from the bottom of the RPV 1. 23 is inserted and the upper end of the motor casing 23 is welded to the opening sleeve 22 to suspend the lower half of the motor casing 23 outside the RPV 1.

In the motor casing 23, a motor shaft 24 and a hollow pump shaft 25, which are keyed so as to be vertically separable, are coaxially rotatably housed.

An impeller 26 is attached to the upper end of the pump shaft 25. A diffuser 27 for diffusing the flow of the coolant is arranged on the outer periphery of the impeller 26. Further, the lower end of the diffuser 27 engages with the upper end of the stretch tube 28, and the stretch tube 28 engages with the stretch tube nut 29, so that the diffuser 27 is fixed on the opening sleeve 22.

On the other hand, the motor portion 21 is composed of a rotor 30 fixed to the outer periphery of the motor shaft 24, a stator 31 and the like arranged on the outer periphery with a predetermined gap, and welded to the lower portion of the RPV 1. It is housed in the motor casing 23. The motor cover 3 has an auxiliary cover 41 at the lower end of the motor casing 23.
2 is clamped and fixed by a stud bolt 36 and a nut 37, and the inside of the motor casing 23 is kept liquid-tight. Further, a secondary seal 44 is arranged in the upper portion of the motor casing 23, and a secondary seal pressure line 60 is connected to the secondary seal 44.

The pump section 20 and the motor section 21 are fastened and fixed to the thrust disk 34 of the motor section 21 by a coupling stud 33 and a coupling stud nut 42 attached to the lower end of the motor shaft 24.

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. With respect to this disassembly, a detachable part, a procedure and the like will be described with reference to FIGS.

First, the nut 37 is loosened and the motor portion 21,
The impeller 26, the pump shaft 25, and the motor shaft 24 are slightly lowered to bring the lower surface of the impeller 26 and the upper surface of the stretch tube 28 into close contact with each other to form a primary seal. Next, the secondary seal 44 is pressurized by the secondary seal pressure line 60 to prevent the reactor water from flowing into the motor casing 23. Then, the reactor water accumulated in the motor casing 23 is drained, and then the auxiliary cover 41 is removed from the motor cover 32. Then remove the coupling stud nut 42 from the coupling stud 33,
After that, 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 out of the system from the lower part of the motor casing 23.

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 the motor casing 23 is attached.
Pour water inside. Then, the secondary seal 44 is released. At this time, the water injected into the motor casing 23 does not leak through the lower closing flange 43.

On the other hand, from the upper side of the RPV 1, the impeller 26, the pump shaft 25, and the motor shaft 24 are thereafter provided.
Take out at the same time. Stretch tube 2 in this state
8 Since the reactor water enters the motor casing 23 through the inside, the upper tube 58 is attached to the inner surface of the upper end of the stretch tube 28 so that the reactor water in the RPV 1 is closed. The upper plug 58 is attached to the fuel exchanger 12
The hoisting machine 15 is used from above.

When the upper plug 58 is attached, the RP
Since the reactor water in V1 does not enter the motor casing 23, the water injected into the motor casing 23 is drained and the lower closing flange 43 is removed. Therefore, finally, the secondary seal 44 should be removed to remove the motor casing 23.
Do from below. After the inspection, the internal pump 11 is attached in the reverse order of the above.

By the way, as for the method of removing the lower closing flange 43 for closing the motor casing 23, the worker is informed that the water inside the motor casing 23 is completely drained by a flow glass (not shown) of a drain line (not shown). It is designed to be removed after confirming in ().

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 when the internal pump 11 is attached in the reverse order of the above.

[0018]

In the above-mentioned conventional lower closing flange 43, when the lower closing flange is removed before the drainage in the motor casing 23 is completely performed by the operator's erroneous operation, the inside of the motor casing is The water injected into the tank leaks out and decontamination work is required. Therefore, there is a possibility that the exposure and the regular inspection period of the worker working below the internal pump 11 may become long.

Further, even when the upper plug 58 is pulled out by mistake during the removal or the attachment of the lower closing flange 43, the reactor water flows in from the inside of the stretch tube 28 and is discharged from the bottom of the motor casing 23. Therefore, decontamination work is required. Therefore, similarly, there is a possibility that the exposure and the regular inspection period of the worker who is working below the internal pump 11 may be prolonged.

The present invention has been made in consideration of the above conventional circumstances, and an object thereof is to prevent the lower closing flange from being removed unless the contaminated water in the motor casing is drained, thereby causing an erroneous operation by an operator. It prevents the diffusion of contaminated water. Further, unless water is poured into the motor casing, the upper plug cannot be pulled out, and similarly, diffusion of contaminated water due to erroneous operation by a worker is prevented.

[0021]

In order to achieve the above object, in the internal pump casing closing device of the present invention, in the invention according to claim 1, the internal pump is vertically installed at the bottom of the reactor pressure vessel and accommodates the internal pump. In the internal pump casing closing device that closes the lower part of the motor casing at the time of periodic inspection, the lower closing flange that has a detecting means that detects the water amount in the motor casing and generates a detection signal corresponding to the water amount, and the lower closing flange Control panel having an interlock that does not generate a start signal when the detected water signal exceeds a predetermined amount, and the lower closing flange is attached to and detached from the lower part of the motor casing by the start signal generated from this control panel. Provided is an internal pump casing closing device having an attaching / detaching device. .

According to the second aspect of the present invention, the upper portion of the motor casing which houses the internal pump vertically penetrating the bottom of the reactor pressure vessel is welded to the inner portion of the bottom of the reactor pressure vessel. Lowering flange having a detection means for detecting the amount of water in the motor casing and generating a detection signal corresponding to the amount of water in an internal pump casing closing device that closes a stretch tube fixed inside the opened sleeve And a control panel having an interlock that receives a detection signal generated from this detection means and does not generate a start signal when the amount of water is below a predetermined amount, and an upper plug that operates by a start signal generated from this control panel. Providing an internal pump casing closure device with an upper plug handling device that attaches to and detaches from the stretch tube It is intended to.

According to a third aspect of the present invention, the detection means is a water load detection means for detecting a static load of water in the motor casing, and the internal pump casing according to the first or second aspect. A closure device is provided.

According to a fourth aspect of the present invention, the detection means is a water level detection means for detecting the water level of the water in the motor casing, and the internal pump casing closing device according to the first or second aspect. Is provided.

According to a fifth aspect of the present invention, there is provided the internal pump casing closing device according to the first or second aspect, wherein the control panel is provided with display means for displaying the amount of water in the motor casing. To do.

[0026]

In the internal pump casing closing device having the above structure, according to the first aspect of the invention, 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 more than a predetermined amount, the control panel is interlocked and the lower closing flange attaching / detaching device does not operate, so that the lower closing flange can be prevented from being removed by mistake.

Also in the second aspect of the invention, the amount of water existing in the motor casing can be detected by the detecting means provided on the lower closing flange. Further, when the amount of water is less than a predetermined amount, the control panel is interlocked and the upper plug handling device is not driven, so that the upper plug can be prevented from being pulled out by an erroneous operation.

According to the third aspect of the invention, the static load of water existing in the motor casing can be detected by the detecting means provided on the lower closing flange. Claim 4
In the described invention, the water level of the water existing in the motor casing can be detected by the detection means provided on the lower closing flange.

According to the fifth aspect of the invention, the amount of water present in the motor casing can be detected by the detecting means provided on the lower closing flange, and the amount of water can be displayed on the control panel.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An internal pump casing closing device according to the present invention will be described below with reference to the drawings. FIG. 1 shows a first internal pump casing closing device according to the present invention.
It is a block diagram of the Example of. The internal pump casing closing device includes a water load sensor 50 for detecting a static load of water.
It has a lower closing flange 43 with. This lower closing flange 43 is raised to the motor casing 23.
It is arranged on a lifter truck 51 that descends. The water load sensor 50 and the lifter carriage 51 have cables 48,
49 is connected, and the other ends of the cables 48 and 49 are connected to the lifter truck 5 based on the information from the water load sensor 50.
It is connected to a control board 52 in which an interlock to 1 is assembled. The control board 52 is connected to the refueling machine control board 56 by a cable 47, and the refueling machine control board 56 is connected to the hoisting machine.

In the internal pump casing closing device thus constructed, the 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. There is.
When a load greater than a predetermined value due to water is detected in the motor casing 23, the lifter truck 51 that raises and lowers the lower closing flange 43 cannot be operated due to the interlock in the control panel 52. Further, when the water in the motor casing 23 is drained and becomes less than a predetermined load, 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 on the control panel 52.

The detection signal from the water load sensor 50 in the motor casing 23 is sent from the control panel 52 to the cable 47.
An interlock is installed so that the upper plug cannot be pulled out by the hoist unless the detection signal exceeds a predetermined load.

FIG. 2 shows a block diagram of a second embodiment of the internal pump casing closing device according to the present invention. Figure 2
In the above, the receiving cable 5 attached to the water level sensor 57 for detecting the water level and the inner wall surrounding the internal pump
A transmitter 53 that transmits a signal to a receiver 55 connected to
The lower closing flange 43 is provided. The lower closing flange 43 is handled by a lifter truck 51 that moves up and down to the motor casing 23. Receiver 5
5 and the lifter truck 51 are connected to the control panel 52 by cables 49 and 54, and the control panel 52 is configured to control the interlock to the lifter truck 51 based on the information signal from the water level sensor 57. Further, the control board 52 is connected to the refueling machine control board 56 by a cable 47.
6 is connected to the hoisting machine.

In the above structure, the motor casing 2
The water in 3 is detected by a water level sensor 57, and the signal is transmitted from a transmitter 53 built in the lower closing flange 43 to a receiver cable 54 connected to an inner wall surrounding the internal pump 11. It is sent to 55 and always reaches the control panel 52. The other operations such as interlock operation and release are the same as those in the first embodiment.

Therefore, according to the present invention, due to the erroneous operation of the operator, the operation of removing the lower closing flange cannot be performed before the water in the motor casing is drained, so that the contaminated water in the motor casing is diffused. To prevent. Therefore, the decontamination work with contaminated water is not necessary and the exposure of the worker can be reduced and the delay of the regular inspection period can be prevented.

Further, the upper plug cannot be removed unless water is poured into the motor casing when the internal pump is mounted, and diffusion of contaminated water due to erroneous operation by a worker is prevented. Therefore, decontamination work with contaminated water is not required, and the exposure of workers can be reduced and the regular inspection period can be shortened.

[0037]

As described above, in the internal pump casing closing device of the present invention, in which the interlock for removing the lower closing flange is incorporated, the lower casing closing flange before the motor casing is drained. It is possible to prevent the water from diffusing in the motor casing due to an erroneous operation of the operator because the operation for removing it cannot be performed.

Further, in the case where an 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 inside of the motor casing is erroneously operated by the operator. It is possible to prevent the diffusion of water. Therefore, the decontamination work with contaminated water is not necessary and the exposure of the worker can be reduced and the delay of the regular inspection period can be prevented.

[Brief description of 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 an internal pump casing closing device according to the present invention.

FIG. 3 is a vertical cross-sectional view around the reactor pressure vessel.

FIG. 4 is a vertical cross-sectional view of an internal pump.

FIG. 5 is an explanatory diagram of an internal pump disassembly procedure.

[Explanation 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 ... Refueling machine 13 ... Trolley 14 ... Suspending rope 15 ... Hoisting machine 16 ... Annular space 17 ... Reactor core 18 ... Water supply nozzle 19 ... Reactor pressure vessel upper lid 20 ... Pump section 21 ... Motor section 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 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 truck 52 ... Control panel 53 ... Transmitter 54 ... Reception cable 55 ... Receiver 56 ... Fuel exchange control panel 57 ... Water level sensor 58 ... Upper plug 59 ... Display panel 60 ... Secondary seal pressurization line

Claims (5)

[Claims] 1. An internal pump casing closing device for vertically suspending a lower portion of a motor casing for accommodating an internal pump, which is hung vertically on a bottom portion of a reactor pressure vessel, to detect the amount of water in the motor casing and corresponds to the amount of water. A lower closing flange having detection means for generating a detection signal, a control panel having an interlock for receiving a detection signal generated by the detection means and not generating a start signal when the amount of water exceeds a predetermined amount, and An internal pump casing closing device, comprising: a detaching device that is actuated by a start signal generated from a control panel to attach and detach a lower closing flange to a lower part of a motor casing. 2. An inside of an opening sleeve that is welded to an upper end of a motor casing that houses an internal pump penetrating the bottom of the reactor pressure vessel and is protruded inside the bottom of the reactor pressure vessel. In the internal pump casing closing device that closes the stretch tube fixed at the time of the periodic inspection, the lower closing flange having the detecting means for detecting the water amount in the motor casing and generating the detection signal corresponding to the water amount, and this detecting means A control panel that has an interlock that does not generate a start signal when the generated detection signal is received and the amount of water is less than a predetermined amount, and an upper part that operates by the start signal generated from this control panel and that attaches and detaches the upper plug to the stretch tube An internal pump casing closing device having a plug handling device. 3. The internal pump casing closing device according to claim 1, wherein the detecting means is a water load detecting means for detecting a static load of water in the motor casing. 4. The internal pump casing closing device according to claim 1, wherein the detecting means is a water level detecting means for detecting the water level of water in the motor casing. 5. The control panel comprises display means for displaying the amount of water in the motor casing.
Alternatively, the internal pump casing closing device according to claim 2.