JPS643105Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention stores and holds a nuclear fuel insert structure underwater in an appropriate disassembly holding device, and by dismantling the structure, the above-mentioned disassembly holding device A nuclear fuel insert remote for dismantling a nuclear fuel insert structure suitable for use in grasping and extracting a used nuclear fuel insert left behind in a nuclear fuel insert and transporting it to a predetermined area for disposal. This invention relates to a gripping and transferring device.

As is known, the nuclear fuel insert structure 1 in a nuclear reactor has a structure as shown in FIG. The upper structure 2 is formed by fitting a hold-down spring 7 into a sleeve 6 that connects the hold-down par 5 and the end plate 3, and the nuclear fuel insert 4 is attached to the upper structure 2. As shown in the figure, there is a burnable poison rod 4 ₁ (stick containing burnable poison) that is several meters long and that controls the reactivity of nuclear fuel, and a rod with a larger diameter and shorter length that controls the reactivity of nuclear fuel. A thimble plug 4 ₂ is used alone or in combination to adjust the pressure loss of the cooling water caused by the atomic bomb, and a nuclear fuel insert as a neutron source is also incorporated in these two 4 ₁ , 4 ₂ . Fuel insert structures and the like are used.

The nuclear fuel insert structure 1 is inserted into a control rod guide single of a nuclear fuel assembly as is known in the art, and used by being press-fixed to the upper core plate via a hold-down spring 7. However, the burnable poison rod ₄₁ described above has the role of absorbing excess neutrons generated by nuclear reactions and maintaining the reactivity of the reactor at a constant level, so it cannot be used while receiving a large amount of neutron irradiation. Since the burned-out burnable poison rod ₄₁ has strong radioactivity and it is dangerous to approach it, conventionally it has been removed from the nuclear fuel assembly to the nuclear fuel insert structure. The nuclear power plant is removed as is by remote control, transported and stored for a long period of time within a designated area of the nuclear power plant.

For this reason, when using the conventional handling described above, the upper structure 2 and the thimble plug ₄₂ , which can be reused unless there is mechanical damage, are discarded together with the burnable poison rod ₄₁ , resulting in a large loss. It has become accompanied by

The present invention focuses on the current situation, and instead of transporting and storing the spent nuclear fuel insert structure 1 as it is, the present invention dismantles the structure 1 underwater to remove burnable poison. Only the rod 4 ₁ is taken out and moved to a designated area as radioactive waste, and a new burnable poison rod is attached to the upper structure 2 of the structure 1, and the same structure 2,
It is intended for reuse of thimble plug 4 ₂ etc.
In particular, in the present invention, the above-mentioned spent nuclear fuel insert structure 1 is pulled out from the nuclear fuel assembly, stored in a holding device for disassembly, and then left undisturbed, the structure 1 is dismantled, and then the nuclear fuel Burnable poison rods, etc., which are inserts, can be taken out of the water and transferred to a separately provided radioactive waste storage area, and new burnable poison rods, etc., can be carried into the holding device for dismantling. Moreover, the purpose is to ensure the safety of such transfer by remote control, and to enable quick and reliable gripping and transfer with simple operations.

To describe the present invention in detail with reference to the illustrated embodiment, as shown in FIG. The main components are an outer cylinder 10 that is fitted onto the rod 9 so as to be able to move up and down, and a gripping operation section 11 that moves the outer cylinder 10 up and down by manual operation.

First, what is illustrated as the hanging portion 8 is the substrate 1
2, both ends of a U-bolt 13 are fixed to protrude upward by tightening nuts 14, and the gripping rod 9 is formed of a pipe, and a connecting rod 9' fitted to the upper end of the pipe is inserted through the base plate 12. Te Natsu 15
By stopping, the gripping rod 9 is suspended from the base plate 12.

The upper end of the outer cylinder 10 fitted into the gripping rod 9 through the gap 16 is fitted onto the connecting rod 9', and the outer cylinder 10 can freely move up and down using the connecting rod 9' as a guide. In the figure, M indicates a sliding area in which the vertical movement is allowed.

Next, the gripping operation section 11 is connected to the substrate 12.
It is equipped with a nut receiving cylinder stand 17 fixedly installed on the lower surface, and a nut with a handle 18 resting in a recessed bottom part 17' of the receiving cylinder stand 17 in a depressed state, and the nut 18 is covered with the outer cylinder 10. It is screwed into the attached screw tube 19,
The handle 18' of the nut with handle 18 is attached to the nut receiver base 1.
The handle 18' extends outwardly from a horizontal elongated hole 20 formed in the peripheral wall of the handle 7, thereby allowing the handle 18' to rotate, for example, by 180 degrees.

Further, the grasping operation part 11 is provided with a mechanism 21 for preventing rotation of the outer cylinder 10, and in the illustrated example, a support arm 22 is horizontally fixed to the outer cylinder 10, and an elevating guide is installed from the support arm 22. The pin 23 is inserted through a guide ring 24 protruding from the nut receiver base 17, and by rotating the handle 18' by 180 degrees as described above, the outer cylinder 10 is attached to the handle. Due to the screw engagement between the nut 18 and the screw tube 19 and the above-mentioned rotation prevention mechanism 21, it is possible to move up and down within the sliding area M without rotating.

Furthermore, in the present invention, a plurality of clamping claws 25, 25... are provided at the tip of the above-mentioned gripping rod 9, and the gripping end opening 26 surrounded by these clamping claws 25, 25... is connected to the lower end. A collector chuck 27 is formed by opening at the opening.

In normal times, the clamping end opening 26 of the collector chuck 27 is held in an expanded state so that the upper end plug 4a of the nuclear fuel insert 4 can be inserted therein, and in the illustrated example, the expanded state is contracted. In order to prevent the gripping rod 9 from becoming loose, a rod core 28 screwed onto the tip of the gripping rod 9 is fitted inside the collection chuck 27 above its axis.

Further, in the case of the illustrated clamping claws 25, 25..., a threaded part 29 is carved on the inner surface forming the clamping end opening 26, and the pitch of the threaded part 29 is inserted into the upper part of the nuclear fuel insert 4. The pitch of the threaded threaded portion 30 formed on the end plug 4a is aligned with the pitch of the threaded threaded portion 30.
If the target is a nuclear fuel insert 4 that does not have zero, it is not necessary to provide such a threaded portion 29. Depending on the target, unevenness (not shown) may be formed instead of the threaded portion. You can also do this.

On the other hand, a sleeve 10' is provided at the tip of the outer cylinder 10.
is fixedly installed, and a pressing tapered surface 31 is formed on the inner circumferential surface of the tip end of the sleeve 10', and the gripping operation section 1
By moving the outer cylinder 10 downward by the rotational operation in step 1, the pressing tapered surface 31 is moved against the clamping claw 2.
The clamping claws 25, 25, .

Therefore, in order to use the above device, first, the spent nuclear fuel insertion structure 1 is removed from the nuclear fuel assembly.
It is lifted up using a bridge crane or the like and stored and placed upright in a dismantling holding device 33 installed separately underwater as shown in FIG.

Here, the holding device 33 for disassembly is a horizontal top plate 35, a horizontal middle plate 3, and a plurality of vertical frame members 34, 34...
6. A horizontal bottom plate 37 is used, and in the illustrated example, the burnable poison rod ₄₁ is installed on the horizontal top plate 3.
5. An upper hole 38 bored in the horizontal middle plate 36,
The lower end plug 4 _1a passes through the middle through hole 39 and is supported by the horizontal bottom plate 37, and the large diameter and short thimble plug 4 ₂ passes through the upper through hole 38 and is supported by the lower end plug 4 _2a. is adapted to be engaged and supported by the middle through hole 39 of the lateral middle plate 36.

Once the nuclear fuel insert structure 1 has been stably placed in water in this way, the upper end plug 4a of the nuclear fuel insert 4 can be opened as shown in FIG. The nut 40 attached to the end plate 3 of the upper structure 2 is removed, and at this time, the fitting body 43 protruding from the step edge 42 of the upper end plug 4a is inserted into the square hole 41 of the end plate 3. A nut 40 with a cylindrical portion 44 is screwed onto the threaded rod portion 30 of the end plug 4a that is fitted and protrudes upward from the end plate 3.
4 is placed in the notch 45 of the threaded rod portion 30 and is caulked, so if a predetermined torque is applied to the nut 40 and the nut 40 is screwed, the anti-rotation cylindrical portion 44 that is caulked in the notch 45 will not be damaged. , nuclear fuel interpolant 4
Since the nut 40 is prevented from rotating by fitting into the square hole 41 of the fitting body 43, the nut 40 can be removed.

The one shown in FIG. 2b is different from the above-mentioned one in that the locking means of the nut 40 screwed onto the upper end plug 4a of the nuclear fuel insert 4 is different from the one shown in FIG.
A pin 47 is fixed to a nut 40 by a welded portion 48 in a vertically cut groove 46, but the above-mentioned fixation by welding can be broken by screwing the nut 40.

After the nuts 40 of all the nuclear fuel inserts 4 have been removed in this way, the superstructure 2 is lifted up by the bridge crane, and the nuclear fuel inserts are placed in the holding device 33 for disassembly. Leave insert 4 behind.

Therefore, only the used burnable poison rod ₄₁ is lifted up by the device according to the present invention and transferred to the desired location as described above. The entire device is suspended by a Tsuji crane or the like and lowered from directly above the burnable poison rod ₄₁ , which is the nuclear fuel inserted in the water. Cylinder 10
is placed in the upward movement position, and therefore the sleeve 10' of the outer cylinder 10 is also placed in the upper position, and its pressing tapered surface 3
1 is located away from the pressure-receiving tapered surface 32 at the position indicated by the two-dot chain line in FIG.
The threaded rod portion 30 of the upper end plug _4a of the burnable poison rod 41 is inserted into the clamping end port 26 which is in the expanded state.
, and then rotate the handle nut 18 in the opposite direction.

By this operation, the outer cylinder 10 moves downward in a non-rotating state as described above, so that the pressing tapered surface 31 of the sleeve 10' comes into sliding contact with the pressure receiving tapered surface 32, and the clamping claws 2
5, 25... are pushed toward the axis, and the clamping end opening 26 is brought into a reduced diameter state.
The threaded portion 29 of... is screwed into the threaded rod portion 30, and the upper end stopper 4a is held by the collection chuck 27.

Next, by operating the bridge crane, the burnable poison rod ₄₁ is moved to the demolition holding device 33.
The radioactive waste will be salvaged and transferred to a designated storage container.

When the burnable poison rod ₄₁ has been pulled out in this manner, a new burnable poison rod is clamped by the above operation and transferred and loaded into the dismantling holding device 33, and when the loading operation is completed, the upper structure 2
The square hole 4 of the end plate 3 is brought in by a bridge crane, and the square hole 4 of the end plate 3 is inserted into the fitting body 43 of the upper end plug 4a of the nuclear fuel insert 4 placed upright in the holding device 33 for disassembly.
1, screw the nut 40 with the cylindrical part 44 onto the threaded rod part 30 with a predetermined tool, and perform the crimping work on the cylindrical part at the notch 45, the regenerated nuclear fuel insert structure can be completed. Once assembled, the structure is lifted from the dismantling holding device 33 by a bridge crane and loaded into a nuclear fuel assembly.

The present invention, as embodied by the above embodiments,
A gripping rod 9 is vertically fixed to the hanging portion 8, which can be lifted by a bridge crane or the like, and a gripping operation portion 11 is also fixed thereon, and is fitted onto the gripping rod 9 in a non-rotating state. The outer cylinder 10 is attached to the gripping operation section 1
A nut with a handle 1 screwed into an outer cylinder 10 in accordance with 1.
It can be moved up and down freely by rotating the gripping rod 9.
At the tip, there are gripping claws 25, 25 divided into multiple pieces.
By providing... nuclear fuel insert structure 1
A collection chuck 27 is formed by opening the gripping end opening 26 into which the upper end plug 4a of the nuclear fuel insert 4 attached to the upper structure 2 of the nuclear fuel insert 4 can be inserted.
The handle nut 18 is attached to the outer circumferential surface of 5, 25...
The pressing tapered surface 31 formed on the inner circumferential surface of the tip of the outer cylinder 10 that has moved downward due to the rotation operation slides into contact with the outer cylinder 10.
Since the clamping claws 25, 25... are formed with a pressure-receiving tapered surface 32 that pushes them in the diametrical direction of the gripping end opening 26, it is possible to eliminate the pressure-receiving taper surface 32 after dismantling the nuclear fuel insert structure, which was previously unimaginable. Therefore, only used radioactive waste can be taken out and disposed of, and reusable members such as the superstructure and thimble plug can be effectively utilized.

In addition, it can be lifted, lowered, and transferred by remote control suspended by the hanging part 8, and by rotating the handle nut 18, the upper end plug of the nuclear fuel insert can be operated quickly and reliably from a remote safe position. It can be gripped underwater, allowing efficient removal of radioactive waste and installation of new nuclear fuel inserts without fear of accidental dropping.

In manufacturing the device according to the present invention, the gripping rod and outer cylinder will actually be long, reaching more than 10 meters, so it is best to connect them with appropriate connecting members, and In order to smoothly move the outer cylinder up and down, it is desirable to insert an appropriate number of guide members in the gap.

[Brief description of the drawings]

Fig. 1 is a front view showing an example of a nuclear fuel insert structure, and Fig. 2 a and b show the attachment points of the nuclear fuel insert to the upper structure in the same structure. FIG. 3 is a partially cutaway front view of the nuclear fuel insert structure housed in the holding device for disassembly; FIG. 4 is a partially cutaway enlarged perspective view of various examples; FIG. FIG. 2 is a partially cutaway front view showing an embodiment of the insert remote grasping and transferring device. 1... Nuclear fuel insert structure, 2... Upper structure, 4... Nuclear fuel insert, 4a... Upper end plug,
8... Hanging part, 9... Gripping rod, 10... Outer cylinder, 1
1...Gripping operation unit, 12...End plate, 13...U
Bolt, 17... Nut receiver stand, 18... Nut with handle, 19... Screw tube, 21... Outer cylinder rotation prevention mechanism, 22... Support arm, 23... Lifting guide pin,
24... Guide ring, 25... Clamping claw, 26... Gripping end opening, 27... Collection chuck, 31... Pressing tapered surface, 32... Pressure receiving tapered surface.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A gripping rod is vertically fixed to a lifting part that can be lifted by a bridge crane, etc., and a gripping operation part is fixedly installed, and a lifting part that can be lifted by a bridge crane, etc. The outer cylinder fitted in the stopped state can be freely moved up and down by rotating a nut with a handle that is screwed into the outer cylinder in the gripping operation part, and the gripping rod is divided into a plurality of pieces at the tip. By providing a clamping claw with a handle, a gripping end opening into which the upper end plug of the nuclear fuel insert attached to the upper structure of the nuclear fuel insert structure can be inserted is opened to form a collector chuck, and the clamping The pressing tapered surface formed on the inner circumferential surface of the tip of the outer cylinder that has been moved downward by the rotation of the handle nut comes into sliding contact with the outer circumferential surface of the claw, and the gripping claw is moved in the diameter-reducing direction of the gripping end opening. A remote grasping and transferring device for a nuclear fuel insert for dismantling a nuclear fuel insert structure, which is formed with a pressure-receiving tapered surface to be pushed. (2) The hanging part is formed by a U-bolt protruding upward from the end plate, and the gripping operation part is attached to a nut receiving stand installed below the end plate, so that it can be rotated freely. A nut with a handle mounted thereon, a screw thread screwed into the nut and fixed to the outer cylinder, and a rotation prevention mechanism of the outer cylinder include a support arm fixed to the outer cylinder and a support arm that is raised from the support arm. and a lifting guide pin inserted into a guide ring protruding from the nut receiver base, the nuclear fuel for dismantling a nuclear fuel insert structure according to claim 1 Insert remote grasping and transfer device.