JPH0516760B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a method for gripping the pump part of an internal pump used in an improved boiling water reactor (ABWR) for attaching and removing the pump part of the internal pump. Regarding equipment.

[Technical Background of the Invention] Generally, as is well known, in a conventional boiling water reactor (BWR), there is The coolant is delivered to the core by forced circulation, but such an external recirculation system not only has a complicated structure, but also
The recirculation piping that connects the reactor pressure vessel and the recirculation pump serves as a boundary for coolant, so if the recirculation piping ruptures due to some kind of accident, there is a possibility of loss of coolant. Therefore, in order to prevent such loss of coolant accidents, an improved boiling water reactor (ABWR) has been developed in which coolant is forced to circulate within the reactor pressure vessel.

Figure 3 is a cross-sectional view of ABWR showing one example.
In the figure, 1 is the reactor pressure vessel. A reactor core 2 consisting of a large number of fuel assemblies (not shown) is formed within the reactor pressure vessel 1, and is housed within a cylindrical shroud 3. A water supply spargeer 5 connected to a water supply pipe 4 is provided above the core 2, and a steam separator 6 and a steam dryer 7 are further provided above the water supply spargeer 5. Further, a plurality of internal pumps 8 are provided in the lower mirror portion of the reactor pressure vessel 1 . As shown in FIG. 4, these internal pumps 8 are composed of a pump section 11 and a motor section 12. By driving the pump section 11 with the motor section 12, the coolant inside the reactor pressure vessel 1 is forcedly circulated. I'm starting to let them do it. The pump section 11 is composed of an impeller 13, a differential user 14, a differential user wear ring 15, etc., and the impeller 13 is connected to the motor section 12 via a drive shaft 16. Further, the diff user 14 is provided at the upper end of a nozzle 17 provided in the lower mirror portion of the reactor pressure vessel 1, and is fixed by a stretch tube 18. The stretch tube 18 is provided in the upper part of the pump casing 20 and is fixed by a stretch tube nut 19. and,
A secondary seal 21 is provided below the stretch tube nut 19.
This prevents the inflow to 2. On the other hand, the motor section 12 is composed of a rotor 22, a stator 23, etc., and is housed within the pump casing 20.
A main flange 24 that closes the lower end opening of the pump casing 20 is attached to the lower end of the pump casing 20. This main flange 24 connects to a plurality of stud bolts 25 provided at the lower end of the pump casing 20, Main flange mounting nut 26 screwed into 25
is firmly fastened to the lower end of the pump casing 20. In addition, the pump casing 2
Cooling water circulation pipes 27 are connected to the upper and lower parts of the motor section 12 to prevent burnout of the motor section 12.

It has an internal pump 8 like this
Since ABWR does not have an external recirculation system like conventional BWRs, it is possible to significantly reduce piping space within the reactor containment vessel and also reduce the capacity of the emergency core cooling system. In addition, since the motor section 12 of the internal pump 8 is housed in the pump casing 20 with excellent watertightness, there is no need for a sliding shaft sealing device, and the structure is simple, reducing the possibility of reactor water leakage. It has excellent safety and reliability because of its small amount. However, with the adoption of such an ABWR with excellent safety and reliability, it is necessary to periodically perform maintenance and inspection work on the internal pump 8. Maintenance and inspection work for the internal pump 8 is performed by first stopping the operation of the reactor, filling the reactor pressure vessel 1 with water, shielding it from radiation, removing the reactor cover 1a of the reactor pressure vessel 1, and then removing the reactor cover 1a from the reactor pressure vessel 1. The furnace well is also filled with water and a steam dryer 7, a steam-water separator 6,
After removing the shroud head 3a, the internal pump 8 is removed from the reactor pressure vessel 1. The removal work of the internal pump 8 is performed from above and below the reactor pressure vessel 1, and the work procedure is as follows.

First, the secondary seal 21 seals between the pump casing 20 and the drive shaft 16 to shut off the reactor water in the reactor pressure vessel 1, and then drains the water in the pump casing 20. Thereafter, the motor section 12 and the main flange 24 are removed from below the pump casing 20. Next, pump casing 20
After attaching the closing flange to the lower end of the pump casing 20 using stud bolts 25,
After filling the inside, the secondary seal 21 is released. In this state, the impeller 1 is viewed from above the reactor pressure vessel 1.
3 together with the drive shaft 16. Next, the opening of the diffuser 14 is closed from above the reactor pressure vessel 1 with an upper closing plate, and the water in the pump casing 20 is drained. In this state, remove the closing flange from below the pump casing 20, and remove the secondary seal 21 and stretch tube nut 19 from inside the pump casing 20. Next, after attaching the closing flange to the lower end of the pump casing 20 again, the pump casing 20 is filled with make-up water. In this state, the upper closing plate, the diff user 14, the diff user wear ring 15, and the stretch tube 18 are removed from above the reactor pressure vessel 1. These are then transported to a maintenance facility for inspection and maintenance. After inspection and maintenance, installation to the internal pump 8 is performed in the reverse order of removal.

[Problems with the Background Art] Incidentally, since the installation and removal work of the pump part 11 of the internal pump 8 is underwater work at a depth of more than 20 meters below the water surface, it is necessary to use a gripping tool operated by, for example, an air cylinder. This is done by remote control from above the reactor pressure vessel 1 using, for example, the reactor pressure vessel 1.
The engagement of the gripping tool with the pump part 11 is visually confirmed by a worker from above the water surface. However, such work has poor work efficiency because it requires remote work in a narrow space underwater.Moreover, if the engagement with the pump part 11 is incomplete, it may fall off during lifting, and the pump part 11 may fall inside the reactor. There is a risk of it falling. In addition, even if the engagement state is perfect, if there is a malfunction or an accident in which the air source is lost, the engagement state may become disengaged and the product may fall into the reactor, which may affect reactor operation. It may cause major trouble.

[Object of the Invention] The present invention has been made based on the above-mentioned circumstances, and its purpose is to provide an internal pump that allows the installation and removal of the pump part to be carried out safely and reliably during maintenance and inspection work of the internal pump. An object of the present invention is to provide a pump part gripping device for a pump.

[Summary of the Invention] In order to achieve the above object, the present invention includes an upper body that is suspended above the pump section of an internal pump by a hoist wire, and an interface that is provided at the lower part of the upper body so as to be movable up and down. a lower main body having a plurality of openable and closable impeller gripping members for gripping the impeller of the null pump; an air cylinder provided in the upper main body for opening and closing the impeller gripping members; and an air cylinder provided in the upper main body and having the lower main body. An indicator light that lights up when the impeller is suspended directly above the impeller, and a suspended weight of the impeller that is inserted into the working air supply pipe that supplies working air to the lower part of the air cylinder and is held by the impeller gripping member. an air cutoff valve that is actuated by the air cylinder to cut off air supply to the air cylinder;
The air cylinder includes a taper cone slidably provided on the piston rod of the air cylinder, a lock member that tightens the taper cone to lock the expansion and contraction movement of the piston rod, and a connecting member that connects the lock member and the lower main body. It is something.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 is a sectional view of a pump part gripping device showing an embodiment of the present invention, in which reference numeral 101 indicates a reactor pressure vessel 1.
The main body of the grip is suspended from above using a hoist wire (not shown). This grip main body 1
01 consists of an upper body 101a that is suspended above the pump section of the internal pump by a hoist wire (not shown), and a lower body 101b that is provided below the upper body 101a so as to be movable up and down. A square stud 102 to which a hoist wire (not shown) is connected is provided at the center of the top surface. This square stud 1
02 is a plate 104 attached to the lower end and a spring 10 incorporated inside the grip main body 101.
It is connected to the grip main body 101 via 3,
The square stud 102 and the plate 104 are moved by the elastic force of the spring 103 according to the weight suspended by the gripping tool.
The gripper body 101 moves up and down relative to the gripper main body 101. This vertical movement operates the microvalve 105 via the plate 104 attached to the lower end of the square stud 102. This micro valve 1
05 supplies air to the lower part of the reciprocating air cylinder 106 built into the grip main body 101;
An operating switch 107 is provided which is activated by the vertical movement of the square stud 102. That is, this activation switch 107 is activated when the square stud 102 moves downward relative to the grip main body 101.
04 comes into contact and turns on, and the square stud 1
02 moves upward relative to the grip body 101, the plate 104 is separated and turned off. When the operating switch 107 is turned on, the micro valve 105 is opened and air is supplied to the lower part of the air cylinder 106. Further, when the operating switch 107 is turned off, the microvalve 105 is closed and the supply of air to the lower part of the air cylinder 106 is cut off.

The air cylinder 106 is connected to the piston rod 10
8 to the upper part of the holder 109. This holder 109 is provided inside a grip part 110 provided at the lower part of the grip main body 101, and is movable in the vertical direction. The gripping portion 110 is the impeller 1 of the internal pump 8.
The impeller gripping mechanism 111 is provided inside the holder 109. The impeller gripping mechanism 111 includes a plurality of impeller gripping members 113 provided in the holder 109 so as to be openable and closable. A portion 115 is formed. This engaging portion 115 is connected to the holder 109.
When it moves up and down, it engages with the hook portion 114 and opens and closes the impeller gripping member 113. That is, when the holder 109 moves upward, the hook portion 114 engages with the engaging portion 115, and the impeller gripping member 113 opens.
Further, when the holder 109 moves downward, the hook portion 114 is disengaged from the engaging portion 115, and the impeller gripping member 113 is closed. Therefore, the impeller gripping mechanism 111 is configured to grip the upper bolt 13a of the impeller 13 by opening and closing the impeller gripping member 113. Furthermore, a detection rod 1 is provided in the center of the holder 109.
16 are provided. This detection rod 116 detects when the upper bolt 13a of the impeller 13 is inserted into the impeller gripping mechanism 111.
is pushed upward by contacting the tip of the plate 117, and operates a limit switch 118 via a plate 117. This limit switch 1
18 is turned on when the detection rod 116 is pushed up, lighting up one of the plurality of indicator lights 119 provided on the upper part of the grip main body 101.

On the other hand, the clipper mechanism 112
It is arranged outside of 9. This clipper mechanism 1
Reference numeral 12 includes a plurality of differential user gripping members 121 each having a claw portion 120 at the tip thereof, and a dogleg-shaped groove 122 is formed in each differential user gripping member 121. A pin 124 fixed to a bracket 123 on the upper part of the holder 109 is inserted into this dogleg-shaped groove 122 and is movable within the groove 122. That is, this pin 124 moves within the groove 122 in response to the vertical movement of the holder 109, and opens and closes the differential user gripping member 121. Therefore, in the clipper mechanism 112, the pin 124 moves within the groove 122 to open and close the differential user gripping member 121, and the claw portion 120 engages with a groove (not shown) formed on the inner surface of the differential user 14. is configured to do so. Further, when the claw portion 120 engages with the groove portion of the differential user 14, the holder 10
A ring 125 protruding from the lower part of the differential user gripping member 121 is configured to be immovable. Note that the clipper mechanism 112 is provided with a limit switch 126, which is turned on when the claw portion 120 engages with the groove portion of the differential user 14.
One of the indicator lights 119 on the upper part of the grip main body 101 is turned on.

Further, a lock mechanism 127 is attached to the piston rod 108 of the air cylinder 106. This lock mechanism 127 is connected to the piston rod 1.
It has a taper cone 130 slidably provided on the outer periphery of the lower body 101 and a press plate 129 as a locking member that tightens the taper cone 130.
connected to b. Therefore, this lock mechanism 1
When 27 tries to pull up the pump part 11 of the internal pump 8, the weight of the lifting force causes the presser member 129 to move downward, and the taper cone 13
The structure is such that the movement of the piston rod 108 is fixed by tightening the piston rod 108. In the figure, 131 is an air supply port, 132 is a waterproof battery box,
133 is a detection switch that comes into contact with the upper end of the diff user 14 to notify that the grip main body 101 has come directly above the internal pump 8.

Next, the operation of this embodiment configured as described above will be explained with reference to FIG. 2. First, square stud 1
One end of the hoist wire is connected to 02, and the grip main body 101 is lowered from above the reactor pressure vessel 1 to just above the internal pump 8. At this time, the rectangular stud 102 is moving downward with respect to the grip body 101 due to the elastic force of the spring 103, so the actuation switch 1 of the micro valve 105 is activated.
07 is turned on, and air is supplied to the lower part of the air cylinder 106. This allows the piston rod 1
08 is pushed upward and moves the holder 109 upward. By moving the holder 109 upward, the impeller gripping mechanism 11 of the gripping portion 110
1 is in an open state as shown in FIG. 2a, and the clipper mechanism 112 is in a closed state and suspended directly above the internal pump 8. When the upper bolt 13a of the impeller 13 is inserted into the open impeller gripping mechanism 111, the tip of the upper bolt 13a contacts the detection rod 116 to operate the limit switch 118, as shown in FIG. 2B. As a result, one of the indicator lights 119 on the upper part of the gripping tool main body 101 lights up, and the upper bolt 13a of the impeller 13 is fixed to the impeller gripping mechanism 1 by the worker above the reactor pressure vessel.
It informs that it has been inserted inside 11. Next, in this state, an operation switch (not shown) is operated to supply air to the upper part of the air cylinder 106 and push the piston rod 108 downward. As a result, the holder 109 moves downward, and due to the downward movement of the holder 109, the impeller gripping mechanism 111 starts a closing operation, and the clipper mechanism 112 starts an opening operation. Then, when the holder 109 is further moved downward, the impeller gripping mechanism 111 is attached to the upper bolt 13 of the impeller 13 as shown in FIG. 2c.
a is gripped by the impeller gripping member 113. Next, when the grip main body 101 is pulled up in this state, the piston rod 108 is fixed to the locking mechanism 127, and the square stud 102 is attached to the grip main body 101.
1, the operating switch 107 of the microvalve 105 is turned off, and the air supply to the lower part of the air cylinder 106 is cut off. As a result, the upper bolt 13a of the impeller 13 is reliably engaged with the impeller gripping mechanism 111, and is pulled out from above the reactor pressure vessel 1. In addition, in the above explanation, the method for removing the impeller 13 of the internal pump 8 was explained.
The clipper mechanism 112 also applies to the differential user 14.
It can be removed in the same way using

In this way, in this embodiment, the grip main body 10
By providing an indicator light 119 on the top of the reactor pressure vessel 1 to display the state of engagement of the grip part 110 with the pump part 11, the state of engagement can be easily confirmed from above the reactor pressure vessel 1. In addition, the grip main body 1
Air cylinder 106 according to the lifting load amount of 01
By providing a micro valve 105 that cuts off the supply of air to the lower part of the pump and a lock mechanism 127 that locks the piston rod 108 of the air cylinder 106, it is possible to lift the pump section 11 even in the event of an erroneous operation or loss of the air source. You can reliably pull it up without letting it go halfway.

[Effects of the Invention] As explained above, according to the present invention, when the lower body is suspended directly above the pump section of the internal pump, the indicator light provided on the upper body lights up, so that the internal pump The impeller can be gripped securely. In addition, when the upper body is lifted after grasping the impeller of the internal pump with the impeller gripping member, the weight of the lifted impeller activates the air cutoff valve, cutting off the air supply to the air cylinder. Even if the cylinder is erroneously operated, the impeller gripping member will not be released, and an accident of the impeller falling off can be prevented. Furthermore, when the upper body is lifted after grasping the impeller of the internal pump with the impeller gripping member, the piston rod of the air cylinder is locked by the taper cone, so even if the air source is lost during lifting, the impeller can be moved to the reactor. It can be removed securely from inside the pressure vessel. Therefore, according to the present invention, it is possible to provide a pump gripping device for an internal pump that can safely and reliably attach and detach the impeller during maintenance and inspection of the internal pump.

[Brief explanation of the drawing]

1 and 2 are diagrams showing an embodiment of the present invention, in which FIG. 1 is a sectional view of a pump gripping device, and FIGS. 2a to 2c are explanatory diagrams showing the operation of the impeller gripping mechanism.
FIG. 3 is a sectional view of the ABWR, and FIG. 4 is a sectional view of the internal pump. DESCRIPTION OF SYMBOLS 1...Reactor pressure vessel, 8...Internal pump, 11...Pump part, 13...Impeller, 14...Diffuser, 101...Gripper main body, 105...Micro valve, 106...Air cylinder, 108...Piston rod, 110...Gripper part , 111... Impeller gripping mechanism, 112... Clipper mechanism, 118,1
26...Limit switch, 119...Indication light, 12
7...Lock mechanism.

Claims (1)

[Claims] 1. An upper body that is suspended above the pump section of the internal pump by a hoist wire, and a plurality of impeller gripping members that are provided at the bottom of the upper body so as to be movable up and down and that can be opened and closed to grip the impeller of the internal pump. a lower body having;
an air cylinder provided in the upper body for driving the impeller gripping member to open and close; an indicator light provided in the upper body that lights up when the lower body is suspended directly above the impeller; an air cutoff valve that is inserted into a working air supply conduit that supplies working air to the lower part of the air cylinder and is operated by the lifting weight of the impeller gripped by the impeller gripping member to shut off air supply to the air cylinder; The air cylinder includes a taper cone slidably provided on the piston rod of the air cylinder, a lock member that tightens the taper cone to lock the expansion and contraction movement of the piston rod, and a connecting member that connects the lock member and the lower main body. A pump part gripping device for an internal pump, characterized by: