JPS63295996A - Control-rod handling apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is applicable to the case where control rods are pulled up from a reactor pressure vessel during periodic inspection of a boiling water reactor (hereinafter abbreviated as BWR). The present invention relates to a control rod handling device used when loading control rods into a reactor core, and particularly relates to a control rod handling device that uses a bayonet coupling as a connection means with a control rod drive mechanism.

(Prior Art) In general, a BWR core is provided with a cylindrical core shroud 2 inside a reactor pressurizing vessel 1, as shown in FIG. Loaded and configured.

The above fuel assembly 3 has an upper grid plate 5 at the top and a fuel support metal at the bottom! The fuel assemblies 3 are supported by a core support plate 7 via A6, and coolant flows into each fuel assembly 3 through an orifice hole 6a of a fuel support fitting 6. Also,
The control rods 4 are connected to a control rod drive mechanism (hereinafter abbreviated as CRD) 8 provided through the bottom of the reactor pressure vessel 1, and a control rod guide tube 9 connected to the core support plate 7 by the CRD 8. The cross-shaped space formed between the four fuel assemblies 3 supported by the fuel support fittings 6 is raised and lowered in the vertical direction.

FIG. 11 shows a conventional connection structure between the control rod 4 and the CRD 8, and 10 is a coupling provided at the lower end of the control rod 4. A coupling spud 11 of the CHD 8 is connected to this coupling 10, and is configured to move the coupling spud 11 up and down with a drive piston (not shown) to drive the control rod 4 up and down.

Further, a lock plug 12 is provided inside the coupling 10 so as to be movable in the vertical direction.
The connection between the control rod 4 and the CHD 8 is released by pushing it upward with the uncoupling rod 13 of the CHD 8. - By the way, when pulling up the control rods 4 from inside the reactor pressure vessel 1 during periodic inspection of BWR, after pulling out the fuel assembly 3 from inside the reactor core, the control rods 4 and CHD
8 and the control rod 4 is pulled up from inside the reactor pressure vessel 1. However, conventional BW
As mentioned above, R pushes up the lock plug 12 to release the connection between the control rod 4 and the CHD 8, so if a foreign object such as crud is caught between the lock plug 12 and the coupling spud 11, the lock will be removed. It became difficult to push up the plug 12, and there was a possibility that the connection between the control rod 4 and the CHD 8 could not be released. Therefore, in order to solve the above-mentioned problems, a control rod using a bayonet coupling as a connection means with the CHD 8 has been proposed.

10(a) to (C) show a connection structure between a control rod and a CRD using a bayonet coupling, and 14 is a bayonet coupling provided at the lower end of the control rod 4. FIG. This bayonet coupling 14 is constructed by arranging retaining projections 16 at approximately 90 degree intervals in the circumferential direction on the inner surface of a hole 15 into which the coupling spud 11 of the CHD 8 is inserted. By rotating the control rod 4 approximately 45 degrees in the circumferential direction from the state b) to the state (C), the connection between the control rod 4 and the CHD 8 is released.

(Problem to be solved by the invention) Ill i using such a bayonet coupling
The ll rod prevents foreign matter such as crud from getting caught between the lock plug and the coupling spud as in the past, so it can reliably disconnect from the CRD, but in order to disconnect from the CRD, The bayonet coupling must be rotated approximately 45 degrees circumferentially. However,
When the bayonet coupling is rotated, the control rod will hit the fuel support fitting, and there is a risk of damaging the Ill control rod. Also, when the control rods are pulled up from the core, the speed limiters of the control rods get caught on the fuel support fittings, so
It is necessary to simultaneously pull up the control rods and fuel support fittings from inside the reactor pressure vessel.

The present invention was made with attention to such problems, and its purpose is to be able to release the connection between the control rod and the CHD using a bayonet coupling, and to connect the control rod and the fuel support fitting. The object of the present invention is to provide a control rod handling device that can simultaneously pull up the control rods from inside the reactor pressure vessel.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a main body that passes through an upper grid plate and is placed on the upper surface of a fuel support fitting, and a main body that a pair of fuel support fitting gripping mechanisms provided at the lower part of the fuel support fitting having a plunger that engages with an orifice hole of the fuel support fitting; and a control rod having a hook provided inside the main body portion and engaging with a handle of the control rod. The present invention is characterized in that it does not include a gripping mechanism and a rotating section that rotates the upper fuel support fitting gripping mechanism and the control rod gripping mechanism integrally with the main body.

(Function) According to the above configuration, since the fuel support fitting gripping mechanism and the control rod gripping mechanism rotate together with the main body, it is possible to release the continuous communication between the control rod and the CRD using the bayonet coupling, and the control rod and the fuel support fittings can be simultaneously pulled up from inside the reactor pressure vessel.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 9.

FIG. 1 shows the control rod handling device according to the present invention lowered into the core of a BWR. The main body part 17 is composed of a main body part 17, and a rotating part 18 that rotates the main body part 17. The main body section 17 is formed by assembling four frame plates 19 into a rectangular tube shape, as shown in FIGS. 2 and 3, and each frame plate 19 is provided with an opening window 20. Further, an upper plate 21 is installed on the upper part of the main body part 17, and a square stud 23 for suspending the main body part 17 from a wire rope 22 of a fuel exchanger (not shown) is provided at the center thereof.

A screw hole 24 is provided in the axial center of the square stud 23, and a bolt (not shown) attached to the tip of the wire loaf 22 is screwed into the screw hole 24 to suspend the main body 17 from the wire rope 22. It has become.

Further, a bottom plate 25 having a cross-shaped opening (not shown) in the center is attached to the lower part of the main body part 17. A corner pin 26 that engages with a positioning groove (not shown) of the fuel support fitting 6 and a side pin 27 that comes into contact with the top surface of the fuel support fitting 6 are protruded from the bottom surface of the bottom plate 25, and each of them penetrates the bottom plate 25. It can be moved up and down.

These corner bins 26 and side pins 27 move upward when the main body 17 is placed on the upper surface of the fuel support fitting 6, and actuate the microswitches 28 and 29 to close the main body 17.
It is designed to light up an indicator light (not shown) provided on the top surface.

Further, a pair of fuel support fitting gripping mechanisms 30A and 30B are provided at the lower part of the main body portion 17. The fuel support fitting gripping mechanisms 30A and 30B are connected to the plunger 31. It is composed of a link mechanism 33, an air cylinder 38, etc., and the plunger 31 is horizontally attached to the lower part of the guide 32 inserted into the coolant flow hole 6b of the fuel support fitting 6, as shown in FIGS. 4(a) and 4(b). It is provided so that it can be slid freely. Also,
One end of a link 33a is connected to the rear end of the plunger 31. The other end of this link 33a has one end as the guide 3
The link mechanism 3 is connected to the other end of the link 33b connected to the link mechanism 3 that slides the plunger 31 in the horizontal direction.
3. Further, a rod 34 is connected to the connecting portion of the links 33a and 33b. This rod 3
4 is connected to one end of a rod 36 via a length adjusting nut 35, and a piston rod 39 of an air cylinder 38 is connected to the other end of the rod 36 via a pin 37. That is, as shown in FIG. 4(b), the plunger 31 slides in the horizontal direction due to the expansion and contraction movement of the piston rod 39, and engages with the orifice hole 6a of the fuel support fitting 6. Note that the air cylinder 38
A limit switch 40 is attached to the holder, and when the piston rod 39 is extended, an indicator light (not shown) provided on the upper surface of the main body 17 is turned on. Further, the plunger 31 is provided with a stopper portion 41 that comes into contact with the inner wall 6C of the fuel support fitting 6.

On the other hand, a control rod gripping mechanism 42 is provided inside the main body portion 17 . This ill WJ bar gripping mechanism 42 has a hook 43. It is composed of an air cylinder 46, a guide 48, etc., and the hook 43 is attached to support frames 44a, 44b.
It is rotatably supported via a shaft 45 therebetween. Also,
The piston rod 47 of the air cylinder 46 is attached to the hook 43.
The piston rods 47 are connected to each other and rotated by the expansion and contraction movement of the piston rod 47. A guide 48 is attached to the lower end portions of the support frames 44a, 44b. This guide 48 is connected to the control rod 4 as shown in FIG.
It guides the handle 4a of the control rod 4 to the position where the hook 43 engages. A microswitch 49 is attached to the air cylinder 46, and when the piston rod 47 is extended, a display ff1 (not shown) provided on the upper surface of the main body 17 is turned on. Further, on the upper surface of the main body 17, there is a pipe joint 50a for supplying working air to the air cylinder j38, 46.
, 50b are provided.

As shown in FIGS. 6 and 7, the rotating section 18 includes four poles 51 that prevent the rotating section 18 from rotating by the upper lattice plate 5, and an upper plate 52 that vertically supports these balls 51. and a lower plate 53, and a stud 55 having a through hole 54 through which the wire loaf 22 is passed is provided at the center of the upper surface of the upper plate 52. Further, a rotating member 56 for rotating the main body portion 17 is provided at the center of the lower plate 53. The rotating member 56 has a square hole 57 at the center of rotation, and the square stud 23 of the main body 17 is fitted into the square hole 57 to rotate the main body 17. Further, a piston rod 60 of an air cylinder 59 is connected to the rotating member 56 via a lever 58, so that it is rotated by the piston rod 60 of the air cylinder 59, as shown in FIG.

Next, the control rods 4 and fuel support fittings 6 are installed in the reactor pressure vessel 1 during periodic inspection using the book 1i configured as described above.
The case of pulling up from inside will be explained. First, Figure 9 (
As shown in a), the control rods 4 are fully inserted into the reactor core in order to maintain the subcriticality of the fuel assemblies 3, and in this state, the two fuel assemblies 3, 3 located at diagonal positions are Pull it out from inside the reactor core. After handling, the control rod guide device 61 consisting of one-to-zero simulated channels 61a and 61b is inserted as shown in FIG. 9(b), and then the remaining two bodies are inserted as shown in FIG. 9(c). Pull the fuel assembly 3.3 out of the core. Next, as shown in FIG. 9(d), the control rod 4 is moved downward by the CRD 8 to be fully withdrawn.

After that, as shown in FIG. 9(e), the control rod guide device 61
After pulling out the control rods from the reactor core, the control rod handling device of the present invention is lowered into the reactor pressure vessel 1 by the wire row 122 of the fuel exchanger, and the main body 17 is attached to the upper surface of the fuel support fitting 6 as shown in FIG. Place it. Here, when the main body 17 reaches the upper surface of the fuel support fitting 6, the corner bin 26 and the side pin 27 move upward, thereby activating the limit switches 28 and 29, and the display provided on the upper surface of the main body 17 is activated. Since the light is lit, it can be confirmed that the main body part 17 is placed on the upper surface of the fuel support fitting 6.

Next, after confirming that the main body part 17 is placed on the fuel support fitting 6, the plungers 31 of the fuel support fitting gripping mechanisms 30A and 30B are pushed out in the horizontal direction by the air cylinder 28, and the orifice of the fuel support fitting 6 is pushed out. At the same time, the hook 43 of the control rod gripping mechanism 42 is rotated by the air cylinder 46 from the solid line position to the imaginary line position in FIG. 2 to engage the handle 4a of the control rod 4.

Next, by driving the CRD 8 and slightly inserting the control rod 4 into the reactor core, or by driving the CRD 8 and inserting the control rod 4 into the reactor core,
By slightly pulling up the control rods 4 and the fuel support fittings 6, the control rods 4 and the fuel support fittings 6 are lifted, releasing the restraint from the core support plate 7, and the rotation prevention device @ (not shown) provided at the bottom of the control rod guide tubes 9 is removed. Release control rod 4. After that, the rotating part 18
The square hole 57 is rotated from the position shown by the solid line in FIG. 8 to the position shown by the imaginary line in FIG.
Rotate 7 approximately 45 degrees. At this time, since the control rod gripping mechanism 42 and the fuel support metal gripping mechanisms 30A and 30B rotate together with the main body 17, the connection between the control rod 4 and the CRD 8 using the bayonet coupling 14 can be released. Note that after the control rod 4 and the CRD 8 are disconnected, the wire 0-722 is wound up, and the control rod 4 and the fuel support fitting 6 are lifted up. During the lifting, the main body 17 is rotated in the opposite direction to the above to return the control rods 4 and fuel support fittings 6 to their normal states, and then the control rods 4 and fuel support fittings 6 are passed through the upper lattice plate 5 and pulled out from inside the reactor pressure vessel 1. increase.

[Effects of the Invention] As explained above, according to the present invention, since the control rod gripping mechanism and the fuel support metal gripping mechanism rotate together with the main body, connection of the control rod and CRD using a bayonet coupling is not possible. It is possible to provide a control rod handling device that can be released and simultaneously pull up a control rod and a fuel support fitting from inside a reactor pressure vessel.

[Brief explanation of the drawing]

Figures 1 to 9 show one embodiment of the present invention. Figure 1 is a sectional view showing the control rod handling device of the present invention lowered into the core of a BWR, and Figure 2 is a cross-sectional view showing the control rod handling device of the present invention lowered into the core of a BWR. 3 is a sectional view showing the main body of the device, FIG. 3 is a sectional view along arrows -■ in FIG. 2, FIG. 4(a) is a detailed view showing the structure of the fuel support fitting gripping mechanism, and FIG. An explanatory diagram showing a state in which the plunger of the fuel support fitting gripping mechanism is engaged with the orifice hole of the fuel support fitting;
Fig. 5 is a sectional view taken along the line v-■ in Fig. 3, Fig. 6 is a front view showing the rotating part of the Tsugu-gobo handling device, and Fig. 7 is a sectional view taken along the line -■ in Fig. 6.
A sectional view taken in the direction of the arrows, jllX8 is an explanatory diagram showing the operation of the air cylinder of the rotating part, Figs. The figures are diagrams for explaining the conventional technology. Fig. 10 is a cross-sectional view showing the core of a BWR, Fig. ~ (C) uses a bayonet coupling as a means of connection with the CRD 7
It is a figure showing the connection structure of C1blJ elJ rod and CRD. 1... Reactor pressure vessel, 3... Fuel assembly, 4...
・Control tilt! , 5... Upper grid plate, 6... Fuel support fitting, 6a... Oriswiss hole, 8... CRD,
DESCRIPTION OF SYMBOLS 14... Bayonet coupling, 17... Main body part, 18... Rotating part, 30A, 30B... Fuel support metal grasping mechanism, 42... Control rod grasping mechanism. Figure 1 Figure 2 Figure 3 (b) Figure 4 Figure 5 Figure 7 and Figure 8 (a) (b) (c) (d) (e) Figure 9 Figure 10 Figure 11 ( a) (C) Figure 12

Claims (1)

[Claims] A pair of fuel support fitting gripping mechanisms having a main body that passes through the upper grid plate and is placed on the upper surface of the fuel support fitting, and a plunger that is provided at the bottom of the main body and engages with an orifice hole of the fuel support fitting. a control rod gripping mechanism provided inside the main body and having a hook that engages with a handle of the control rod; and a rotating part that rotates the fuel support fitting gripping mechanism and the control rod gripping mechanism integrally with the main body. A control rod handling device comprising: