JPH0718948B2 - Diffuser wear ring handling device for internal pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an internal pump for handling a diffuser wear ring of an internal pump in a new boiling water reactor (hereinafter referred to as A-BWR). The present invention relates to a diffuser wear ring handling device for a pump.

(Prior Art) Generally, in a boiling water reactor (BWR), a coolant recirculation system for forcibly feeding a coolant (for example, water, hereinafter referred to as coolant) of a reactor pressure vessel into a core is provided. It is provided. FIG. 3 is a view showing the structure of a conventional BWR, and reference numeral 1 in the drawing is a reactor pressure vessel. A reactor core 2 including a plurality of fuel assemblies and control rods is housed in a shroud 3 in the reactor pressure vessel 1. A water supply sparger 5 connected to the 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 sparger 5.

On the other hand, a plurality of jet pumps 8 are installed in the downcomer portion formed by the shroud 3 and the inner wall of the reactor pressure vessel 1. These jet pumps 8 jet the cooling water supplied from the recirculation pump 10 through the coolant recirculation system pipe 9 as a jet flow below the core 2. In the figure, reference numeral 11 is a main steam pipe for taking out steam generated in the reactor pressure vessel 1, and reference numeral 12 is a control rod.
A control rod drive mechanism for controlling the output of the nuclear reactor by inserting 13 into the core 2.

In the BWR having such a configuration, the cooling water supplied from the water supply pipe 4 into the reactor pressure vessel 1 flows out from the water supply sparger 5, flows down the downcomer part, is sucked by the recirculation pump 10, and is connected to the recirculation system piping. It is supplied to the jet pump 8 via 9. Further, this jet pump 8 enables the core 2
And is forcedly sent into the core 2.
When the cooling water forcedly fed into the core 2 rises in the core 2, the temperature of the cooling water rises due to its nuclear reaction heat and becomes a two-phase flow state of water and steam. The cooling water in the two-phase flow state is steam-water separator 6
It is introduced into the inside and separated into water and water. The separated steam is introduced into the steam dryer 7 and dried to become dry steam. This dry steam is the main steam pipe connected to the reactor pressure vessel 1.
It is transferred to a turbine (not shown) via 11 and is used for power generation there. The steam that has worked in the turbine is introduced into a condenser (not shown) to be condensed water, and is supplied as low-temperature cooling water into the reactor pressure vessel 1 through the water supply pipe 4.
The water separated by the steam separator 6 flows down in the downcomer part together with the water supplied from the water supply sparger 5, and the recirculation pump
Aspirated by 10. The same cycle is repeated thereafter.

By the way, in such a conventional BWR, a recirculation pump 10 for supplying cooling water as a driving flow to the jet pump 8 is installed outside the reactor pressure vessel 1, and some accident or the like occurs. When the recirculation system pipe 9 is broken by this, the cooling water will flow out of the reactor pressure vessel 1.
Such outflow of cooling water significantly lowers the core cooling performance, and may damage the fuel rods constituting the fuel assembly. Therefore, in the conventional BWR, the core 2
An emergency core cooling system is installed separately for emergency cooling. However, when such an emergency core cooling system is installed, there is a problem that the amount of equipment, pipes, etc. increases, the configuration becomes complicated, and the plant becomes larger.

Therefore, the above-mentioned A-BWR is considered. This A-BWR is a so-called internal pump type BWR, and has a structure in which an internal pump is housed in the reactor pressure vessel 1. The structure of the A-BWR will be described below with reference to FIGS. 4 and 5. Figure 4 shows A-
It is sectional drawing which shows the structure of BWR, and FIG. 5 is sectional drawing which shows the structure of an internal pump. The same parts as those in FIG. 3 are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 20 in the figure is an internal pump. A plurality of the internal pumps 20 are installed in the lower portion between the reactor pressure vessel 1 and the shroud 3 at equal intervals in the circumferential direction. As shown in FIG. 5, the internal pump 20 is composed of a pump section 21 and a motor section 22. The pump unit 21 includes an impeller 23, a diffuser 24, a diffuser wear ring 25, and the like. The impeller 23 is a drive shaft
The motor unit 22 is connected via 26. The diffuser 24 is a nozzle projecting from the bottom of the reactor pressure vessel 1.
It is fixed to the upper part of 1a by a stretch tube 27. The stretch tube 27 is fixed by a stretch tube nut 28. A secondary seal 29 is installed below the stretch tube nut 28.

The motor unit 22 is composed of a rotor 30, a stator 31 and the like. The components of the motor unit 22 are such that the tip portion is inserted into the nozzle 1a and the tip portion is inserted into the reactor pressure vessel 1 It is housed in a pump casing 32 welded to the. Cooling water circulates in the pump casing 32 through a circulation pipe 33 to prevent the motor unit 22 from being burned. The diffuser
A guide sleeve in which the drive shaft 26 is inserted at the center of the lower part of 24
24a is provided integrally with the diffuser 24.

Since the A-BWR having such an internal pump 20 does not have a structure having a recirculation pump outside the reactor pressure vessel 1 like the BWR described above, a structure equivalent to a conventional recirculation system piping is required. do not do. Therefore, the installation space in the primary containment vessel, the reactor containment vessel, can be significantly reduced, and the assumed fracture cross-sectional area in the liquid phase portion can be greatly reduced. Further internal pump
As for 20 as well, the motor unit 22 is housed in the pump casing 32 having excellent watertightness and does not require a sliding type shaft sealing device, so the configuration is simple and the possibility of leaking reactor water is small, Not only reliability but also maintainability is excellent.

However, even in the case of such an internal pump 20, it is necessary to inspect it regularly. The inspection work of this internal pump will be described below. The work of removing the internal pump 20 is performed from above and below the reactor pressure vessel 1. In that case, first, the impeller 23 is removed together with the drive shaft 26 from above the reactor pressure vessel 1, and the opening of the diffuser 24 is opened. To prevent the inflow of reactor water. Next, after discharging the reactor water in the pump casing 32, the motor unit 22 is removed from below the reactor pressure vessel 1.
And the secondary seal 29 and stretch tube nut
28 is removed from below the reactor pressure vessel 1. Next, the lower surface of the pump casing 32 is sealed to prevent the reactor water from flowing out, and then the diffuser 24, the diffuser waring 25 and the stretch tube 27 are removed from above the reactor pressure vessel 1.

However, the work for removing or installing such an internal pump needs to be performed remotely in a narrow space, and it is expected that the work will be difficult. Especially the diffuser wear ring 25 built into the upper part of the diffuser 24
Is a wear member, and it is difficult to attach and detach because it is a small part compared to other parts.As a result, the work time required for maintenance and inspection work is prolonged, and there is a concern that workers will be exposed to radiation and the operation of the plant. It is not preferable for improving the rate.

(Problems to be solved by the invention) As described above, attachment / detachment work of the internal pump, particularly attachment / detachment of the diffuser wear ring is accompanied by difficulty, which prolongs the work, resulting in radiation exposure of workers and plant operation rate. Therefore, the present invention has been made on the basis of this point, and the purpose thereof is to easily attach and detach the diffuser wear ring, thereby simplifying the work and reducing the work time. An object of the present invention is to provide a diffuser wear ring handling device for an internal pump capable of shortening the above.

[Configuration of the Invention] (Means for Solving the Problems) That is, the diffuser wear ring handling device of the internal pump according to the present invention is a handling device main body that is suspended from above and can be taken in and out of a reactor pressure vessel, The diffuser wear ring gripping mechanism attached to the handling device body to grip the diffuser wear ring of the internal pump, and the diffuser wear ring gripping mechanism attached to the handling device body and the handling device body to push the diffuser wear ring up. A diffuser wear ring lifting mechanism for removing the diffuser wear ring gripped by the gripping mechanism from the diffuser of the internal pump, wherein the diffuser wear ring lifting mechanism comprises a plurality of cylinder mechanisms attached to the handling device body. A cylinder table which is connected to the lower end of the piston rod of the cylinder mechanism via a connecting rod and which abuts against the guide sleeve of the diffuser by the downward extension operation of the piston rod. is there.

(Operation) In other words, when removing the diffuser wear ring of the internal pump, the handling device main body equipped with the diffuser wear ring gripping mechanism and the diffuser wear ring lifting mechanism is hung from above into the reactor pressure vessel at the specified position. Install. Next, the diffuser wear ring gripping mechanism grips the diffuser wear ring, and in that state, the diffuser wear ring lifting mechanism pulls it up.
After that, the handling device body is unloaded.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. The configurations of the A-BWR and the internal pump will be described with reference to FIGS. 4 and 5 used for explaining the conventional example. FIG. 1 is a front view showing a partially cutaway configuration of a diffuser wear ring handling device for an internal pump according to this embodiment, and FIG. 2 is a plan view. In the figure, reference numeral 101 is a handling apparatus body, and a stud 101a is fixed to the upper portion of the handling apparatus body 101. When the handling apparatus body 101 is carried into the reactor pressure vessel 1, the handling device body 101 is attached to the stud 101a. By connecting an operation ball and a wire rope (not shown), they are hung down from above and carried in. A diffuser wear ring gripping mechanism 102 is attached to the lower portion of the handling device body 101, and the diffuser wear ring gripping mechanism 102 grips the diffuser wear ring 25. Positioning guides 103 are attached in the vicinity of the diffuser wear ring gripping mechanism 102 at four positions as shown in FIG.

The diffuser wear ring gripping mechanism 102 includes an air cylinder 104a installed in the apparatus body 101 and a piston rod slidably installed in the air cylinder 104a.
It is composed of 104b and two arms 105, 105 connected to this piston rod 104b. A claw member 106 is fixed to the tips of these arms 105. The claw member 106 grips the groove 25a (shown in FIG. 5) formed on the upper side surface of the diffuser wear ring 25.

The positioning guide 103 has a diffuser wear ring 2
Four locking pins 25b (shown in FIG. 5) planted on the upper surface of 5 penetrate from below. As a result, the handling device body 101 is accurately positioned. Positioning guide 103 above
A lever 107 is attached to the upper part of this lever.
Is pushed up by the locking pin 25b penetrating the positioning guide 103, which activates the limit switch 108. The lamp 110 is turned on via the battery 109 by the operation of the limit switch 108. This confirms that the handling device main body 101 is installed at a predetermined position. Further, reference numeral 111 in the figure denotes an air supply port through which air for operation is supplied to the air cylinder 104a. Then, by supplying air, the air cylinder 104a
Is operated to grip the claw member 106 (closing operation, first operation).
(Indicated by the arrow in the figure), the block 112 moves in the direction indicated by the arrow in FIG. 1 to activate the limit switch 113. The lamp 114 is turned on by the operation of the limit switch 113. This confirms that the diffuser wear ring 25 is held by the diffuser wear ring gripping mechanism 102 .

Reference numeral 115 in the figure is a diffuser wear ring lifting mechanism. The pulling mechanism 115 grips the diffuser wear ring 25 by the gripping mechanism 102 and then pulls it up and removes it. As shown in FIGS. 1 and 2, the pulling mechanism 115 includes a plurality of air cylinders 116a attached to the handling apparatus main body 101 and a lower end of a piston rod 116b attached to the lower side of the air cylinders 116a. The base 118 is connected via a connecting rod 117. That is, when operating air is supplied to the air cylinder 116a from the air supply port 111, the connecting rod 117 projects downward via the piston rod 116b. As a result, it is pushed through the base 118, which causes the diffuser wear ring 25
Pull up. The lower part of the device body 101 is covered with a cover 119. This is to protect small parts, pipes, cables, etc. installed in the lower part of the handling apparatus main body 101. Reference numeral 121 in the drawing denotes a guide roller, and when the handling apparatus main body 101 is carried into the reactor pressure vessel 1, the guide roller 121 is run along a rail laid inside the reactor pressure vessel 1. .

The operation will be described based on the above configuration. First, the handling device main body 101 is suspended from above the reactor pressure vessel 1 using an operation pole and a wire rope. And the handling device body 1
The guide roller 121 attached to 01 is installed in the reactor pressure vessel 1
It is run along a rail (not shown) provided inside and is positioned directly above the internal pump 20. When the handling apparatus 101 is further lowered, the locking pin 25b penetrates the positioning guide 103 from below, whereby the position of the handling apparatus body 101 is determined. Locking pin 2
The lever 107 is urged by the tip of the 5b to operate the limit switch 108. This turns on the lamp 110.
By turning on the lamp 110, it can be confirmed that the handling apparatus main body 101 is positioned at a predetermined position. At this time, the claw member 106 of the gripping mechanism 102 is in the opened state (the state shown in FIG. 1), and the diffuser wear ring 25
Located on the upper side of the. Next, air is supplied to the air cylinder 104 of the grip mechanism 25 to slide the piston rod 105 upward in the figure. Due to the sliding of the piston rod 105, the two arms 105 are pulled upward as shown by the chain double-dashed line in FIG. Then block 1
12 moves to actuate limit switch 113, causing lamp 114 to illuminate. This confirms that the claw member 106 has grasped the diffuser wear ring 25.
Next, when air is supplied to each air cylinder 116a of the diffuser wear ring pull-up mechanism 115 to extend the piston rod 116b downward, the piston rod 1 is pulled through the connecting rod 117.
The base 118 connected to the lower end of 16b contacts the guide sleeve 24a of the diffuser 24. Air cylinder 116
When the piston rod 116b of a is further extended, the handling device body 101 and the diffuser wear ring gripping mechanism 102 are
Is pushed upwards. In this way, the diffuser wear ring 25 is pulled up. That is, since the diffuser wear ring pull-up mechanism 115 is incorporated in the handling apparatus main body 101, a clad or the like may enter between the diffuser 24 and the diffuser wear ring 25,
Or diffuser wear ring 25 by neutron irradiation
Even if it is deformed, it can be removed reliably and easily. When the handling apparatus body 101 is carried out from the reactor pressure vessel 1 in this state, the work of removing the diffuser wear ring 25 is completed.

According to this embodiment, the following effects can be obtained.

(1) First, by using the handling apparatus according to the present embodiment, the diffuser wear ring 25 can be easily and quickly attached and detached even in a narrow space. Therefore, the work is facilitated and the work time is shortened, so that it is possible to reduce the radiation exposure of the workers and improve the operating rate of the plant.

(2) Further, the positioning of the handling device main body 101 can be surely performed by fitting the positioning guide and the locking pin 25b, and it can be confirmed by turning on the lamp 110, so that the remote operation is also possible. It will be certain.

(3) This is the same when the diffuser wear ring 25 is gripped by the claw member 106, and can be confirmed by turning on the lamp 114.

(4) Further, by providing the diffuser wear ring pulling mechanism 115 that pushes up the handling apparatus main body 101 and the diffuser wear ring 102, the diffuser 2
Even if a clad or the like enters between 4 and the diffuser wear ring 25, or the diffuser wear ring 25 is deformed by neutron irradiation, it can be removed reliably and easily.

[Effects of the Invention] As described above in detail, according to the diffuser wear ring handling device for an internal pump of the present invention, the diffuser wear ring of the internal pump can be easily removed even in an extremely narrow space. By doing so, maintenance and inspection work can be facilitated and the time required for the work can be greatly reduced. Therefore, it is possible to reduce the radiation exposure of workers and improve the operating rate of the plant.
Further, even if the clad or the like is inserted between the diffuser and the diffuser wear ring, or the diffuser wear ring is deformed by neutron irradiation, the diffuser wear ring can be reliably and easily removed.

[Brief description of drawings]

1 and 2 are views showing an embodiment of the present invention. FIG. 1 is a sectional view of a diffuser wear ring handling device, FIG. 2 is a plan view of the diffuser wear ring handling device, and FIG. 3 is boiling. Sectional drawing which shows the schematic structure of a water reactor, FIG. 4 is sectional drawing which shows the schematic structure of a new boiling water reactor, and FIG. 5 is sectional drawing which shows the structure of an internal pump. 22 …… Internal pump, 25 …… Diffuser wear ring, 101 …… Handling device body, 102 …… Diffuser wear ring gripping mechanism, 115 …… Diffuser wear ring lifting mechanism.

Claims (2)

[Claims] 1. A handling device main body which is suspended from above into a reactor pressure vessel and which can be taken in and out, a diffuser wear ring gripping mechanism which is attached to the handling device main body and grips a diffuser wear ring of an internal pump, and the above-mentioned handling. The diffuser wear ring gripping mechanism incorporated in the main body of the apparatus and the diffuser wear ring pulling mechanism for lifting the diffuser wear ring from the diffuser of the internal pump by pushing up the handling apparatus main body, and the diffuser wear ring pulling mechanism. Includes a plurality of cylinder mechanisms attached to the handling device body, and a pedestal that is connected to the lower ends of the piston rods of these cylinder mechanisms via connecting rods and that is extended by downward extension of the piston rods. Inter that is characterized by Null pump diffuser wear ring handling device. 2. A positioning guide is attached to the handling apparatus body, and a locking pin protruding from the upper end of the diffuser wear ring is fitted into the positioning guide to determine the position of the handling apparatus body. The diffuser wear ring handling device for an internal pump according to claim 1, characterized in that.