JP2000206281A - Fuel assembly handling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel assembly handling device capable of attaining dose reduction of workers in detaching a separator from a MOX fuel assembly and surely detaching without damaging the separator and the fuel assembly. SOLUTION: For a fuel assembly handling device for detaching a separator 103 installed in a MOX fuel assembly 101 after taking the MOX fuel assembly 101 out of a fuel transportation vessel, a chuck mechanism 106d for detaching the separator 103 supported at a specific level in the vicinity of a fuel inspection stage 105 capable of moving up and down and turning the MOX fuel assembly 101 is provided with a mechanism horizontally moving by a reciprocal air cylinder 106.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for handling fuel assemblies in a reactor building of a nuclear power plant,
More particularly, the present invention relates to a fuel assembly handling apparatus suitable for removing a separator attached to a fuel assembly containing MOX fuel, which is a mixed fuel of plutonium oxide and uranium oxide (hereinafter referred to as MOX fuel assembly). .

[0002]

2. Description of the Related Art Generally, in a boiling water reactor, which is an example of a light water reactor, a fuel assembly containing uranium oxide fuel (hereinafter referred to as a uranium fuel assembly) secures fuel integrity during transportation. For this purpose, a jig called a separator that properly maintains the fuel rod spacing is installed, stored in a dedicated fuel transport container, transported into a nuclear power plant, taken out of the fuel transport container, and inspected for fuel. Will be After that, it is temporarily stored in a storage facility such as a spent fuel pool with the channel box attached, and then loaded into the reactor.

[0003] In the case of a uranium fuel assembly, the radiation rate emitted from the fuel assembly is low. Therefore, when removing the separator, it is necessary to handle the uranium fuel assembly without using special equipment for protecting the radiation. It was possible.

[0004]

[0005] Compared to the conventional operation of handling a uranium fuel assembly, the following problems are concerned with the MOX fuel assembly.

[0005] After the MOX fuel assembly carried into the reactor building while being stored in the fuel transport container is removed from the fuel transport container, the fuel assembly is removed from the fuel holder protecting the fuel assembly. After that, it is necessary to remove dozens of separators mounted over the entire length of the fuel assembly.

At this time, the worker receives the radiation emitted from the MOX fuel assembly at a short distance. MOX
Since the fuel assembly has a relatively high dose rate of radiation emitted from the fuel assembly as compared with the uranium fuel assembly, it is necessary to consider the reduction of the worker's exposure. For this reason, workability is inevitably deteriorated, such as restriction of proximity work and limitation of work hours.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the exposure of an operator when removing a separator from a MOX fuel assembly, and to remove the separator reliably and without damaging the separator and the fuel assembly. It is to provide a possible fuel assembly handling device.

[0008]

In order to achieve the above object, the present invention provides a fuel assembly comprising a MOX fuel, which is a mixed fuel of plutonium oxide and uranium oxide, taken out of a fuel transport container. In a fuel assembly handling device for removing a separator attached to a fuel assembly, a chucking mechanism for removing the separator is provided near a fuel inspection table capable of vertically moving or rotating the fuel assembly. And a mechanism movable in the horizontal direction by a pneumatic cylinder.

According to the present invention, it is possible for a worker to perform a separator removing operation at a remote position by using a chucking mechanism which is a dedicated separator removing device, instead of the conventional manual removal by a worker. is there. Therefore, it is possible to reduce the exposure of the fuel handling worker, and to ensure that the separator mounted over the entire length of the MOX fuel assembly can maintain the integrity of the separator and the fuel assembly without giving an excessive load. Can be secured and removed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 2 shows a fuel transport container 10.
FIG. 2 is a schematic diagram showing a state where the MOX fuel assembly 101 is stored in a fuel holder 102 at 0. The MOX fuel assembly 101 is a comb-shaped jig called a separator 103 shown in FIG. 3 and has a plurality of engaging grooves 104 on both sides. As shown in FIG. 4, dozens of the MOX fuel assemblies 101 are mounted on the opposite surfaces of the MOX fuel assembly 101 at the same height position.
02, and the fuel transport container 10
In the state of being stored at 0, it is transported from the MOX fuel processing plant to the work area of the reactor building in the nuclear power plant. As described above, special consideration is given to the MOX fuel assembly 101 to prevent damage during transportation from the processing plant to the nuclear power plant. MO brought into nuclear power plant
The X fuel assembly 101 has the fuel holder 10 before the fuel inspection.
2 and the separator 103 are removed. In particular, the separator 103 has a large number of attachments, and the removal work is MO.
It must be performed at a close distance of the X fuel assembly 101,
From the viewpoint of work efficiency and reduction of worker exposure, the removal work needs to be remotely operated and mechanized.

An embodiment of the present invention will be described with reference to FIG.
The MOX fuel assembly 101 is installed on the fuel inspection table 105 with the separator 103 mounted. When removing the separator 103 mounted on the MOX fuel assembly 101, the separator 103 is removed using a separator removal device 106 set on the floor of the work area. As a work procedure,
First, the MOX fuel assembly 1 is set so that the position of the separator 103 is at the height of the separator removal device 106 facing the separator 103.
01 is moved in the vertical direction by the fuel test stand 105.

Next, the forward / backward moving air cylinder 106a of the separator removing device 106 is operated, and the removing head 10 is removed.
6b is advanced in the direction of the MOX fuel assembly 101. Thereafter, the chuck air cylinder 106c is operated to hold the separator 103 by the chuck mechanism 106d, and then the front-rearward air cylinder 106a is operated again to move the chuck mechanism 106d backward from the MOX fuel assembly 101, and the removal of the separator 103 is completed. I do.

The above operations are all performed in the MOX fuel assembly 101.
Since the operation is performed from the console 106e installed at a position several meters away from the operator, the exposure of the worker is reduced. The removed separator 103 is put on a belt conveyor 107 installed below the separator removing device 106, and
After being transported to a position several meters away from the OX fuel assembly 101, the operator stores it in a collection container.

By repeating the above operation, all the separators 103 mounted on the same surface of the MOX fuel assembly 101 are removed. When removing the separator 103 mounted on the other surface, the MOX fuel assembly 101 installed on the fuel inspection table 105 is lowered and stored in the pit 108, and the surface to be removed is the separator removal device. 1
The separator 103 is rotated so as to face the same as 06, and all the separators 103 attached to the MOX fuel assembly 101 can be removed by repeating the same operation as described above.

On the upper surface of the pit 108, a shielding plate 109 having an opening through which the MOX fuel assembly 101 can be moved up and down and rotated can be installed.
Also when performing the rotation operation 01, the exposure from the MOX fuel assembly 101 placed in the pit 108 can be reduced. In the case where the fuel inspection table does not have the function of moving the fuel assembly vertically, the same effect can be obtained by providing the separator removing device with the function of moving vertically.

Next, an embodiment of the separator removing mechanism will be described. FIG. 5 is a schematic view of the connection between the separator removal device 106 and the MOX fuel assembly 101. The separator 103 is mounted at the same position in the vertical direction on the opposing surface of the MOX fuel assembly 101, and holds the fuel rod 110.

As shown in FIG. 3, the separator 103 has a plurality of grooves 104 on both sides of the outer frame 103a.
When removing the separator 103, the chuck mechanism 10
A plurality of pull-out pins 111 provided in 6d are inserted into this groove 104, and a mechanism for preventing slippage during pull-out is provided.

This pull-out pin 111 is used for the chuck mechanism 10.
6d are attached to both side surfaces, and the insertion depth δ is detected by an optical non-contact type sensor 112 installed near the extraction pin 111, so that each extraction pin 111 is inserted into the groove 104. Can be determined.

Further, in the step of removing the separator 103 using the electric signal detected by the sensor 112 described above, the extraction pin 111
If at least a plurality of the separators 103 are not inserted, an interlock can be constructed so that the chuck mechanism 106d does not shift to the gripping operation of the separator 103, and the pulling-out operation of the separator 103 can be more reliably performed.

FIG. 5 shows a spring structure as an example of an insertion mechanism of the pull-out pin 111. The function of the spring 113 is the pull-out pin 1
11 is pressed with a constant force. This spring 11
If the pressing force of 3 is too strong, an unnecessary (excess) load will be applied to the outer frame 103a of the separator when the pull-out pin 111 is not correctly inserted into the groove 104 of the separator 103. As a result, the outer frame 1 of the separator 103
03a may be deformed and its soundness may be impaired.

On the other hand, if the pressing force of the spring 113 is too weak, for example, when a minute vibration or displacement occurs during the detaching operation of the separator 103, the extracting pin 111
It is possible to deviate from 4. Therefore, the pressing force of the spring 113 needs to be defined in an appropriate range.

FIG. 6 is a diagram showing an example of the arrangement of the pull-out pins 111. The arrangement of the pull-out pins 111 is two rows and three steps, and the pitch of each row is matched with the pitch of the groove 104 provided in the outer frame 103a of the separator 103. However, the position of the pull-out pins 111 of each row is shifted by, for example, about 10 mm. Therefore, even if the height position of the separator 103 to be removed and the separator removing device 106 are slightly shifted,
Can be reliably inserted into the groove 104.

Next, when removing the separator 103, M
A method for eliminating torsion when the OX fuel assembly 101 is twisted or the like and the separator removing device 106 and the MOX fuel assembly 101 are not relatively parallel will be described. In such a situation, the extraction pin 111 is not inserted into the groove 104 of the separator 103, and there is a concern that removal may be hindered. Therefore, by installing a holding plate 114 for holding the facing surface of the MOX fuel assembly 101 above the separator removing device 106, the MOX fuel assembly 101
Is removed, and the separator 103 can be removed without any trouble.

The holding plate 114 is provided for the MOX fuel assembly 101.
Use nylon or rubber material for the contact area with
Care must be taken not to impair the soundness even when contacting the MOX fuel assembly 101. The operation of the holding plate 114 is performed by moving the holding plate air cylinder 114a back and forth.
X fuel assembly 101 is pressed. This operation needs to be performed before the operation of the separator removing device 106.

Further, as shown in FIG. 7, when the position of the separator 103 to be removed and the relative position of the separator removing device 106 are greatly shifted, and the gripping operation is performed by the chuck mechanism at the position where the separator is not mounted. In the meantime, there is a concern that the removal head 106b may directly contact the fuel rod 110 and damage it. In order to avoid such a situation, an optical non-contact sensor 115 is installed near the chuck mechanism 106d to determine the presence or absence of a separator. If there is no separator, an interlock is provided so as not to shift to a gripping operation. It is possible to increase the reliability at the time of construction and removal.

[0026]

According to the present invention, when the separator is removed from the MOX fuel assembly in the reactor building, it is possible to reduce the exposure of the worker, and accordingly, the handling workability of the MOX fuel assembly can be reduced. Without having to make things worse. Further, the removal operation can be performed reliably and without damaging the separator and the fuel assembly, and the operation ensuring the soundness of the separator and the MOX fuel assembly can be performed.

[Brief description of the drawings]

1A and 1B are diagrams showing an embodiment of a fuel assembly handling apparatus according to the present invention, wherein FIG. 1A is a schematic configuration diagram, and FIG.

FIG. 2 is a schematic diagram showing a state in which a MOX fuel assembly is stored in a fuel transport container.

FIG. 3 is a schematic configuration diagram of a separator.

FIG. 4 is a diagram showing a state where a separator is mounted on the MOX fuel assembly.

FIG. 5 shows a separator removing apparatus and a MOX according to the present invention.
2A and 2B are diagrams showing the arrangement of fuel assemblies, wherein FIG. 2A is a schematic configuration diagram, and FIG.

FIGS. 6A and 6B are diagrams showing the arrangement of the separator removing device and the separator according to the present invention, wherein FIG.
(B) is a detailed view of a portion A in (a).

FIG. 7 is a view showing the arrangement of a separator removing device and a sensor for determining the presence or absence of a separator according to the present invention.

[Explanation of symbols]

100: fuel transport container, 101: MOX fuel assembly, 1
02: Fuel holder, 103: Separator, 103a: Outer frame, 104: Groove, 105: Fuel inspection table, 106: Separator removal device, 106a: Front / rearward air cylinder, 106
b: removal head, 106c: air cylinder for chuck, 106d: chuck mechanism, 108: pit, 109
... Shield plate, 110 ... Fuel rod, 111 ... Pull pin, 11
2,115: sensor, 113: spring, 114: holding plate.

 ──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Masao Takenaka 3-1-1 Sachimachi, Hitachi-City, Ibaraki Prefecture Inside the Hitachi Works, Ltd. Hitachi, Ltd. (72) Inventor Shinichi Okuda 3-2-2 Sachimachi, Hitachi-City, Ibaraki Prefecture No. 1 Hitachi Engineering Co., Ltd. (72) Inventor Hiroyuki Ishikawa 3-2-2 Komachi, Hitachi City, Ibaraki Prefecture Inside Hitachi New Clear Engineering Co., Ltd.

Claims (5)

[Claims] 1. A fuel assembly for removing a separator mounted on a fuel assembly after removing a fuel assembly containing a MOX fuel which is a mixed fuel of plutonium oxide and uranium oxide from a fuel transport container. In the handling device, a chucking mechanism for removing the separator,
A fuel assembly, comprising: a mechanism that is supported at a predetermined height near a fuel inspection table that can move or rotate the fuel assembly in a vertical direction and that is movable in a horizontal direction by a pneumatic cylinder. Handling equipment. 2. The fuel assembly handling apparatus according to claim 1, wherein a state of inserting a pin for pulling out the separator into the groove for locking the separator is identifiable. 3. The fuel assembly handling apparatus according to claim 1, wherein a plurality of pins for pulling out the separator are arranged, and a step is provided at a pin position of each arrangement. 4. The fuel assembly according to claim 1, wherein a support plate for holding a part of the facing surface of the fuel assembly is provided above the fuel assembly handling apparatus. Handling equipment. 5. The fuel assembly handling apparatus according to claim 1, wherein an identification device for confirming a side surface of the separator is provided near a pin for pulling out the separator.