JPS6312557B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a direct-acting refueling device that remotely handles fuel assemblies in a nuclear reactor, and particularly to a fuel exchanging device that can identify the fuel assemblies held therein.

FIG. 1 shows a conventional fast breeder reactor using liquid metal as a coolant, which will be explained below.

In the figure, reference numeral 1 denotes a furnace vessel, and the upper end opening of this furnace vessel 1 is closed by a fixed plug 2, a large-rotation plug 3, and a small-rotation plug 4 eccentrically provided on the large-rotation plug 3. Furnace vessel 1
A reactor core 6 supported by reactor internals 5 is located inside the reactor, and the reactor is filled with liquid metal 7 as a coolant. This liquid metal 7 is guided into the reactor vessel 1 from the coolant inlet 8 at the bottom of the reactor vessel 1, and is introduced into the reactor core 6.
The coolant is discharged from the furnace vessel 1 through the coolant outlet 9 at the upper part of the furnace vessel 1, and is then discharged from the furnace vessel 1 again from the coolant inlet 8.
It is guided and circulated within. Further, in the upper part of the reactor vessel 1, a fuel exchange device 10 for exchanging fuel assemblies in the reactor core 6 is installed, penetrating the small rotating plug 4 and extending to a position directly above the reactor core 6.

As shown in FIG. 1, this fuel exchange device 10 includes a door valve 11 for shutting off the inside of the furnace and the outside;
A gripper guide pipe 13 that extends below the door valve 11 and passes through the small rotation plug 4 via a guide sleeve 12 to prevent shrinkage due to sliding, and a casing that extends above the door valve 11 and shields it from the outside. a drive section 16 for operating the gripper 15 located within the fuel assembly 14; and a gripper support tube 17 extending downward from the drive section 16;
The gripper 15 is attached to the lower end of the gripper support tube 17.

As shown in FIG. 2, this gripper 15 includes a finger 19 that is pivotally mounted in a gripper support cylinder 17 via a pin 18, an actuator 20 that moves up and down to open and close this finger 19, and an actuator 20 that moves up and down to open and close this finger 19. The finger 19 is composed of an actuator drive shaft 21, and has a claw 22 projecting outward from the lower end of the finger 19. The gripper 15 and the fuel assembly 23 are connected by opening the fingers 19 and engaging the claws 22 with the handling head 24 at the upper end of the fuel assembly 23.

The conventional fuel exchange device has the above configuration,
As mentioned above, the structure is complicated, and since the finger claws are used for engagement with the fuel assembly, there are problems in terms of strength, and the mechanism inevitably becomes large. Furthermore, when rotating or pushing the fuel assembly into the reactor core, the finger claws are not fixed to the handling head, making it difficult to operate. Furthermore, since fast reactors use opaque liquid metal as a coolant, it is not possible to directly see the fuel assemblies gripped by the grippers, so it is necessary to confirm whether the fuel assemblies gripped are the correct ones. However, with conventional products, this cannot be confirmed in the coolant.

The present invention has been made to solve these conventional problems, and its purpose is to facilitate rotation and pushing of a gripped fuel assembly, and to ensure that the gripped fuel assembly is correct. An object of the present invention is to provide a fuel exchange device that can identify and confirm the presence or absence of fuel in a coolant.

The present invention will be explained below based on an embodiment shown in FIGS. 3 to 14.

In FIG. 3, reference numeral 1 denotes a furnace vessel, and the upper end opening of this furnace vessel 1 is closed by a fixed plug 2, a large-rotation plug 3, and a small-rotation plug 4 eccentrically provided on the large-rotation plug 3. A reactor core 6 supported by reactor internals 5 is located inside the reactor vessel 1, and a liquid metal 7 as a coolant is located inside the reactor.
filled with. This liquid metal 7 is in the furnace vessel 1
The coolant is introduced into the furnace vessel 1 from the lower coolant inlet 8,
The coolant is discharged from the reactor vessel 1 through the reactor core 6 from the coolant outlet 9 in the upper part of the reactor vessel 1, and is again guided into the reactor vessel 1 from the coolant inlet 8 and circulated. Further, in the upper part of the reactor vessel 1, a fuel exchange device 30 for exchanging the fuel assemblies of the reactor core 6 is extended to a position directly above the reactor core 6 passing through the small rotating plug 4.

As shown in FIG. 3, this fuel exchange device 30 includes a door valve 11 for shutting off the inside of the furnace and the outside;
A gripper guide pipe 13 that extends below the door valve 11 and passes through the small rotation plug 4 via a guide sleeve 12 to prevent shrinkage due to sliding, and a casing that extends above the door valve 11 and shields it from the outside. 14, it is composed of a drive part 26 located inside the casing 14 and operating a gripper 25 for gripping the fuel assembly, a hollow shaft 27 extending downward from this drive part 26, etc., and the gripper 25 is located at the lower end position of the hollow shaft 27. It is arranged.

As shown in FIGS. 4 to 7, the gripper 25 includes an upper gripper 28 fixed to the lower end of the hollow shaft 27, and a central shaft 29 that is loosely fitted into the hollow shaft 27 and whose lower end protrudes downward from the upper gripper 28. A lower gripper 31 is fixed to the lower end of the gripper.

As shown in FIGS. 4 and 5, the upper gripper 28 is composed of three arms 28a that protrude horizontally at equal intervals in the circumferential direction. upward-pointing claws forming a chevron shape 3
2 are provided protruding from each other. Further, the lower gripper 31 has three arms 31a that protrude horizontally in correspondence with the arm 28a, as shown in FIGS. 4 and 7.
On the lower surface side of the tip of each arm 31a, there is an arm 3.
In the width direction of 1a, downwardly directed claws 33 each having a chevron shape are provided to protrude.

Further, as shown in FIG. 8, the drive unit 26 of the gripper 25 is built into a housing 34 that surrounds the upper end portions of the hollow shaft 27 and the central shaft 29, and is built into the housing 34 for each shaft.
Drive motors 35, 36 for rotationally driving 7, 29,
Lock devices 37, 38 that lock the vertical movement of each shaft 27, 29, markers 39, 40 provided on the circumferential surface of each shaft 27, 29, a detection device 41 that detects the vertical position of each marker 39, 40, 42,43,4
4, 45, etc., and the housing 34 has wires 46
It is designed to move up and down by winding and unwinding.

Gears 47 and 48 and contraction parts 49 and 50 are provided at the positions of the hollow shaft 27 and the center shaft 29 inside the housing 34, respectively, and each gear 47 and 48 is connected to each drive via a gear mechanism 51 and 52. Motor 35,3
6, and each of the reduced diameter portions 49, 50 is adapted to be engaged with each of the locking devices 37, 38, respectively.

In FIG. 8, reference numerals 53 and 54 are springs disposed around the center shaft 29, and these springs 53 and 54 maintain an appropriate vertical distance between the grippers 28 and 31.

On the other hand, the fuel assembly 63 handled by the fuel exchange device 30 is provided with a handling head 64 at its upper end, as shown in FIG.

As shown in FIGS. 9 to 11, this handling head 64 includes an upper donut-shaped disk 65,
A ring-shaped groove is formed on the inner peripheral surface of the hollow cylinder from the thin cylinder 66 and the lower thick cylinder 67. As shown in FIGS. 9 to 12, the upper donut-shaped disc 65 is provided with the grippers 2.
Notches through which the arms 28a and 31a of 8 and 31 can pass
68 are provided at three locations corresponding to the arms 28a, 31a, and on the lower surface side of this disk 65, as shown in FIGS. 9 and 12, claws 3 of the upper gripper 28 are provided.
A groove 69 and a stopper 70 are provided, respectively. Further, on the upper surface side of the lower thick-walled cylinder 67, as shown in FIGS. 9 and 13, there is a groove 71 in which the pawl 33 of the stopper 31 located directly below the notch 68 is engaged, and between the adjacent grooves 71. A signal groove 72 for identifying the fuel assembly 63 is provided at each position. This signal groove 7
The position or number of 2 differs depending on each fuel assembly 63, so that each fuel assembly 63 can be identified.

Next, the operation of the fuel exchange device 30 according to this embodiment will be explained.

In order to grip the fuel assembly 63 with the stopper 25, first, the arm 28a of the upper gripper 28 and the arm 31a of the lower end gripper 31 are stacked vertically, and then the housing 34 is attached to the handling head by unwinding the wire 46. 64. The gripper 31 is then inserted into the handling head 64 through the notch 68.

Next, the claws 33 of the lower gripper 31 are engaged with the grooves 71 of the lower thick-walled cylinder 67, and the central shaft 29 is locked by the locking device 38 to prevent the lower gripper 31 from moving up and down.

Next, the drive motor 35 is started to move the hollow shaft 27.
is rotated to fit the claw 32 at the tip of the arm 28a of the upper gripper 28 into the groove 69 of the upper donut-shaped disc 65. Thereafter, it is locked by the locking device 37 to prevent the upper gripper 28 from moving up and down. As a result, the gripper 25 is fixed in position within the handling head 64 and is reliably prevented from coming off. Further, since the claw 33 and the groove 71 are in close contact with each other, it is possible to reliably transmit the pushing force to the fuel assembly 63 even when pushing the fuel assembly 63.

When rotating the fuel assembly 63, the hollow shaft 27 and the central shaft 29 are rotated synchronously by the drive motors 35 and 36. As a result, the fuel assembly 63
will rotate in the required direction.

FIG. 14 is a developed view of FIG. 9 viewed from the direction of the arrow, showing the behavior of the pawls 32, 33 during each operation within the handling head 64. This will be explained below.

First, when gripping the fuel assembly 63 with the gripper 25, the tips of the claws 32 and 33 are at the positions indicated by broken lines A and C when the gripper 25 is inserted into the handling head 64. That is, in FIG. 8, the markers 39 and 40 are located at the positions of the detection devices 41 and 45.

Next, when the upper gripper 28 is rotated, the claws 32
The tip of is lowered to the position of broken line B. The position of the marker 39 will be lowered to the position of the detection device 42. When the rotation is completed and the claw 32 is fitted into the groove 69, the position of the tip of the claw 32 returns to the position indicated by the broken line A, and the marker 39 also returns to the position of the detection device 41.

Thus, the fact that the gripper 25 is completely connected to the handling head 64 means that the marker 40 on the central shaft 29 is at the position of the sensing device 45 and the marker 39 on the hollow shaft 27 is at the position of the sensing device 41. This can be confirmed by detection.

Incidentally, in order to separate the gripper 25 and the fuel assembly 63, the procedure described above may be reversed.

Next, when identifying the gripped fuel assembly 63, first, the gripper 25 releases the vertical movement lock by the locking device 38 with the gripper 25 gripping the fuel assembly 63.

Next, the central shaft 29 is rotated to move the pawl 33 from the groove 71 of the lower thick-walled cylinder 67 to the adjacent groove 71 in the rotational direction. During this time, the claw 33 is connected to the signal groove 7.
It will rotate while falling to 2.

As shown in FIG. 14, when the pawl 33 is fitted into the groove 71, the tip of the pawl 33 is at the position of the broken line C, and as the pawl 33 rotates, the position of the tip changes between the dotted line E and the dotted line D. It changes alternately between. By the way, the positions of the broken lines C, D, and E can be confirmed by detecting the markers 40 on the central shaft 29 with the detection devices 43, 44, and 45, so that while the claws 33 rotate between the adjacent grooves 71, Signal groove 72 passing through
The number and position of can be confirmed by simultaneously detecting the number of signals from the detection devices 44 and 45 and the rotation angle of the central shaft 29. Therefore, by changing the number and angle of the signal grooves 72 for each fuel assembly 63, each fuel assembly 63 can be identified by detecting this using the method described above.

In addition, in the embodiment, each gripper 28,
The arms 28a and 31a of 31 are three, and the claws 32 and 3 are
I explained about the one with 3 as a chevron, but the arm 28
The number of the claws a, 31a is not limited to three, but may be two or four or more, and the claws 32, 33 may be formed in an arc shape.

The present invention has been described above based on preferred embodiments, but according to the present invention, since no fingers are used in the gripper, the structure is simple and the mechanical strength can be increased. Therefore, it is possible to downsize the device.

Furthermore, since the gripper is securely fixed in position within the handling head, the connection is strong and there is no risk that the gripper and fuel assembly will separate during operation. In addition, sufficient pushing force can be applied to the fuel assembly when pushing the fuel assembly, and since the gripper and the fuel assembly are integrated, the fuel assembly can be easily rotated when pushing the fuel assembly. .

In addition, since it is possible to detect relative vertical position fluctuations of the upper and lower grippers, it is possible to check the connection between the grippers and the fuel assembly and to check whether the fuel assembly gripped by the grippers is the correct one. It becomes possible. As a result, there is no risk of handling the wrong fuel assembly, and the safety and reliability of fuel exchange can be improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional example, Fig. 2 is an enlarged view of the main part of Fig. 1, Fig. 3 is a sectional view showing an embodiment of the present invention, and Fig. 4 is an enlarged view of the main part of Fig. 3. Perspective view, 5th
The figure is a sectional view of Figure 4 seen from above, and Figure 6 is a cross-sectional view of Figure 5.
Figure 7 is a bottom view of Figure 6,
8 is an enlarged cross-sectional view of the main part of FIG. 3, FIG. 9 is a perspective view showing the upper end portion of the fuel assembly according to the present invention in cross section, FIG. 10 is a plan view of FIG. 9, and FIG. 11 is 1st
Figure 12 is a cross-sectional view taken along the line XII--XII in Figure 11, Figure 13 is a cross-sectional view taken along the - line in Figure 11, and Figure 14 is the behavior of the gripper in the handling head during each operation. FIG. 9 is a developed cross-sectional view of FIG. 9 viewed from the direction of the arrow. 25...Gripper, 27...Hollow shaft, 28...Upper gripper, 28a, 31a...Arm, 29...Center shaft, 3
0... fuel exchange device, 31... lower gripper, 32,
33...Claw, 35, 36...Drive motor, 37, 38
...Lock device, 39,40...Marker, 41,4
2, 43, 44, 45...detection device, 47, 48...
Gear, 51, 52...Gear mechanism, 63...Fuel assembly, 64...Handling head, 65...Upper donut-shaped disk, 66...Thin cylinder, 67...Lower thick cylinder, 68...Notch, 69, 71...Groove , 70...Stopper, 72...Signal groove.

Claims (1)

[Scope of Claims] 1. An upper gripper provided at the lower end of a hollow shaft and having a plurality of arms projecting horizontally at equal intervals in the circumferential direction; and a central shaft that is loosely fitted into the hollow shaft and whose lower end projects downward from the upper gripper. a lower gripper provided at the lower end of the apparatus and having a plurality of arms protruding horizontally in correspondence with the upper gripper;
A claw protruding upward from the upper surface of the tip of each arm of the upper gripper, a claw protruding downward from the lower surface of the tip of each arm of the lower gripper, and rotationally driving each of the axes. The gripper is equipped with a drive device and a detection device that detects relative vertical positional fluctuations of both grippers, and the grippers are aligned in the rotational direction and inserted into the handling head at the upper end of the fuel assembly from the notch thereof, and the lower Lock the claws of the side grippers in the fixing grooves directly below the notch on the lower surface of the handling head, and rotate the upper gripper to the stopper groove position on the upper surface of the handling head to prevent both grippers from coming out from the handling head. The detection device detects the vertical positional fluctuation of the upper gripper as the claws of the upper gripper are locked in the stopper groove, and confirms that the upper gripper is not pulled out. The lower gripper is rotated in the locked state, and the detection device detects the vertical positional fluctuation of the lower gripper caused by its claws passing through fuel assembly identification grooves provided on the lower surface of the handling head. A fuel exchange device characterized in that a fuel assembly is identified by a fuel assembly. 2. Claim 1 characterized in that both grippers have three arms, the claws of each arm are formed in a mountain shape, and each groove of the handling head is V-shaped to correspond to the shape of the claws. Fuel exchange device as described in section.