JPH0584879B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a nuclear reactor fuel exchange device for fast breeder reactors and the like, which is installed in a nuclear reactor vessel and performs fuel exchange with the reactor core.

[Conventional technology]

First, FIG. 3 shows the conventional configuration of the fuel exchange device mentioned above. In the figure, 1 is the reactor vessel housing the reactor core 2, 3 is the shielding plug installed on its top surface, 4 is the rotating plug attached to the center of the fixed plug 3, and 5 is the offset arm installed on the rotating plug 4. It is a type fuel exchange device. Here, fuel exchange device 5
is equipped with a drive part 51 at the top of the outside of the furnace, and a main shaft part 52 inserted into the inside of the furnace through the rotary plug 3;
A hold down tube 54 is attached to the side of the main body shaft portion 52 via an offset arm 53.
, a gripper 55, etc., which is operated to move up and down along the internal fuel passage of the hold-down tube 54.

The operation of such a fuel exchange device 5 is well known, and the hold down tube 54 is moved to the core 2 side by a positioning operation in combination with the rotation of the rotary plug 4 and the rotation of the main body shaft portion 52 of the fuel exchange device 5. A designated position is accessed and the gripper 55 is raised and lowered at this position to perform fuel exchange such as removing fuel and loading.

On the other hand, an in-core relay device 6 is installed on the side of the reactor core 2 in addition to the fuel exchange device 5 inside the reactor vessel in order to carry out the spent fuel extracted from the reactor core 2 and to carry new fuel into the reactor. It is configured to carry in and out fuel via the in-furnace relay device 6 to a fuel loading/unloading machine 7, which is a fuel transfer facility located outside the furnace. The shielding plug 3 is provided with a fuel inlet/outlet passage 31 and a door valve 32 thereof. Here, the spent fuel extracted from the reactor core 2 is delivered to the in-core relay device 6 by moving the fuel exchange device 5, following the path shown by arrow A, and from there, by lifting the fuel inlet/output device 7, along the path shown by arrow B. It is carried out of the furnace by following the path. On the other hand, contrary to the above, the new fuel is once delivered to the in-core relay device 6 by the lifting and lowering operation of the fuel inlet/outlet device 7, and from there, the fuel is received by the operation of the fuel exchange device 5 and loaded into the reactor core 2.

[Problem that the invention seeks to solve]

As described above, in the conventional fuel exchange apparatus, the fuel contained in the hold-down tube is suspended and gripped by the gripper from above, not only during fuel extraction and loading operations, but also during the fuel transportation process within the reactor. Therefore, when carrying in and out of fuel, even if it is attempted to transfer fuel directly between the fuel exchange device 5 and the fuel intake/discharge machine 7, the gripper on the fuel exchange system side and the gripper on the fuel intake/discharge machine side will They interfere with each other from the same direction, making it impossible to transfer fuel. For this purpose, conventionally, the in-core relay device 6 is installed inside the reactor vessel as described above, and when carrying in and out fuel, the fuel is transferred to the relay point of the in-core relay device 6 by the gripper of the fuel exchange device or The fuel is transferred after being disconnected from the gripper of the fuel inlet/outlet machine.

However, disposing the in-core relay device 6 on the side of the reactor core 2 inside the reactor vessel 1 as described above not only complicates the in-reactor structure but also
The reactor vessel 1 becomes larger in diameter, and the reactor containment vessel also becomes larger accordingly, leading to an increase in the construction cost of the nuclear reactor equipment.

The purpose of this invention is to enable direct transfer of fuel between the fuel exchange device and the fuel transfer equipment outside the reactor without going through the in-core relay device, thereby omitting the in-core relay device. It is an object of the present invention to provide a fuel exchange device for a nuclear reactor, which allows the entire nuclear reactor equipment including the reactor vessel to be made smaller and more compact.

[Means for solving problems]

In order to solve the above problems, the present invention provides a rotation avoidance mechanism that avoids the gripper to the side of the top of the holddown tube, and a rotation avoidance mechanism that avoids the gripper toward the side of the top of the holddown tube, and a rotation avoidance mechanism that prevents the gripper from moving in and out of the fuel passage in the holddown tube from the side. It shall be constructed with a lower support stand.

[Effect]

In the above configuration, when replacing fuel, the gripper is located at the center of the hold-down tube,
With the lower support stand retracted out of the fuel passage, exchange operations such as loading and unloading fuel with the core are performed by raising and lowering the gripper. On the other hand, when carrying in and out fuel, the gripper is rotated to the side of the top of the hold-down tube and the lower support is protruded into the fuel passage, and the hold-down tube is connected to the fuel transfer equipment outside the reactor. By moving the hold-down tube to the corresponding position, fuel can be transferred directly between the fuel transfer equipment and the hold-down tube without interference with the gripper.

〔Example〕

1 and 2 show the structure of a fuel exchange device according to an embodiment of the present invention, and the same members corresponding to those in FIG. 3 are given the same reference numerals.

That is, according to this invention, first, the fuel exchange device 5
The gripper 55 of the hold down tube 54
offset arm 53 in its lateral position parallel to
The lifting guide rail 8 supported by the lift guide rail 8 is connected via a nut 10 to a ball screw 9 installed here, and the ball screw 9 is connected to the gear mechanism 1 at the lower end side.
1. It is transmission-connected to the drive part 51 of the fuel exchange device 5 via the drive shaft 12. Further, the guide rail 8 has an offset arm 53 so as to be able to rotate around its axis while mounting and supporting the gripper 55.
The guide rail 8 is supported by a bearing, and the guide rail 8 is transmission-connected to a drive section 51 via a gear mechanism 13 and a drive shaft 14 provided on the circumferential surface of the guide rail 8.

With this configuration, when the drive shaft 12 is rotated in any direction by the drive unit 51, the gripper 55 is threaded by the ball screw 9 and is moved up and down in the direction of arrow A. Also, by rotating the drive shaft 14, the gripper 55 is moved to the guide rail 8.
At the same time, the rotation operation is performed in the direction of arrow B. The length of the ball screw 9 is selected so that the gripper 55 can be raised to a position further above the upper end of the hold-down tube 54 and pulled out.

On the other hand, an openable and closable lower support stand indicated by reference numeral 56 is provided at a midway point in the lower part of the fuel passage in the hold-down tube 54 . This lower support stand 56
is operated by its operating mechanism to rotate in and out from the rear in the direction of arrow C toward the inside of the fuel passage, and the lower support base 56 serves as the operating mechanism.
is transmission-coupled to a drive unit 51 of the refueling device via a gear mechanism (not shown) coupled to the rear end and a drive shaft 15.

Next, a description will be given of the fuel transfer operation performed between the fuel transfer equipment outside the reactor having the above configuration and the fuel inlet/output machine, and the fuel exchange operation performed between the reactor core and the reactor core. When carrying in new fuel from outside the reactor and loading it into the reactor core, first position the rotary plug 4 and the main body shaft part 52 of the fuel exchange device by rotating the hold-down tube 54 to open the fuel inlet/outlet to the fixed plug 3. Move it to the position directly below 31. Next, as shown in FIG. 1, the gripper 55 is raised to the uppermost position and pulled out from the hold-down tube 54, and the lower support base 56 is further protruded into the fuel passage in the hold-down tube as shown in the figure, and then the gripper is removed. The gripper 5 is rotated by rotating the guide rail 8.
5 is moved sideways from the top of the hold-down tube 54 as shown in FIG. Next, in this state, the fuel 1 is
6 is suspended into the reactor through the fuel inlet/outlet 31 of the fixed plug 3, accommodated in the hold down tube 54 waiting just below, and landed and supported on the lower support base 56, after which the gripper of the fuel inlet/outlet machine 7 is and the fuel 16, and then rotate the guide rail 8 to return the gripper 55 to the center position of the hold-down tube 54.

This completes the transfer operation of new fuel into the reactor, and then lowers the gripper 55 to remove the fuel 1.
6, the fuel 16 is once raised together with the gripper, and the lower support 56, which has been protruding into the fuel passage as shown in the figure, is moved backward from the fuel passage so as to be inverted in a vertical position. Next, the hold-down tube 54 is accessed to a designated position on the core side by a positioning operation according to the rotation of the rotary plug 4 and the rotation of the main body shaft 52 of the fuel exchange device 5, and at this position, the gripper 55 is lowered. Fuel 16 is loaded into the core.

On the other hand, when the spent fuel is extracted from the core and carried out of the reactor, contrary to the above operation, the lower support 56 is first retracted from the fuel passage of the hold-down tube 54, and then the rotary plug and fuel exchanger The hold-down tube 54 is accessed to a designated position on the core side by the rotational positioning operation in step 5, and the gripper 55 is operated here to extract the spent fuel from the core and collect it in the hold-down tube. Next, while holding the fuel 1 with the grippers 55,
6 is raised to the highest position, the lower support stand 56 is operated to protrude into the fuel passage, and the gripper 55 is again lowered to move the fuel 16 to the lower support stand 56.
to land on top of. Next, use Gritzpa 55 as fuel 1
6, lift the gripper 55 again to pull it out of the hold-down tube, and then
As shown in the figure, the guide rail 8 is rotated to avoid rotation of the gripper 55 toward the top side of the hold-down tube 54.

Next, the fuel exchange device 5 is moved to the delivery position outside the reactor while still containing the fuel 16, and here the fuel inlet/output machine 7 outside the reactor is operated to lift up the spent fuel accommodated in the hold-down tube 54. and remove it from the furnace. Furthermore, hold down tube 5
4 and the fuel inlet/outlet device 7, the gripper 55 is prevented from rotating to the side of the top of the hold-down tube 54 as described above, so there is no interference with the gripper 55. The fuel 16 can be directly transferred between the fuel exchange device 5 and the fuel intake/discharge machine 7.

〔Effect of the invention〕

As described above, according to the present invention, there is provided a rotation avoidance mechanism that avoids the gripper toward the top side of the hold-down tube, and a lower support for supporting fuel that is operated from the side to enter and exit the fuel passage in the hold-down tube. With the gripper positioned at the center of the hold-down tube and the lower support stand retracted outside the fuel passage, fuel exchange is performed between the core and the gripper by the vertical position of the gripper, and the gripper is positioned at the center of the hold-down tube. By avoiding rotation of the top to the side and directly transferring fuel between the fuel transfer equipment outside the reactor and the hold-down tube with the lower support protruding into the fuel passage, this design eliminates the need for conventional equipment. It is possible to omit the in-core relay device that was previously used and to directly transfer fuel to the fuel transfer equipment outside the reactor, which simplifies the reactor internal structure and improves the efficiency of reactor equipment including the reactor vessel. It is possible to make it smaller and more compact.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the entire structure of a fuel exchange device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the main structure of FIG. 1, and FIG. 3 is a block diagram of a conventional fuel exchange device. In each figure, 1...Reactor vessel, 2...Reactor core, 4...Rotating plug, 5...Fuel exchange device, 7...Fuel inlet/output machine of extra-core fuel transfer equipment, 8...Gripper guide rail, 9...Ball screw for gripper lifting/lowering operation, 1
3...Gear mechanism of gripper rotation avoidance mechanism, 14...
... Drive shaft of gripper rotation avoidance mechanism, 51 ... Drive section of fuel exchange device, 52 ... Main body shaft section, 53 ...
Offset arm, 54... hold down tube, 55... gripper, 56... lower support base.

Claims (1)

[Claims] 1. A nuclear reactor fuel exchange device installed on the upper rotating plug of a reactor vessel to exchange fuel with the reactor core, which is equipped with a drive section at the top and is mounted and supported on the rotating plug. A gripper comprising: a main body shaft; a hold down tube supported on the side of the main body shaft via an offset arm; and a gripper that is operated up and down along the hold down tube. A rotation avoidance mechanism that avoids the top of the down tube to the side, and a lower support for supporting fuel that is operated from the side into and out of the fuel passage in the hold down tube, and the gripper is located at the center of the hold down tube, Then, with the lower support stand retracted outside the fuel passage, fuel is exchanged with the reactor core by raising and lowering the gripper, the gripper is prevented from rotating to the side of the top of the hold-down tube, and the lower support stand is removed from the fuel passage. A fuel exchange device for a nuclear reactor, characterized in that it is configured to directly transfer fuel between a fuel transfer facility outside the reactor and a holddown tube in a state that projects into a passage. 2. In the fuel exchange device according to claim 1, the guide rail of the gripper, which is rotatably supported by the offset arm of the fuel exchange device, is driven via a gear mechanism and a drive shaft, as the gripper rotation avoidance mechanism. A fuel exchange device for a nuclear reactor, characterized in that the device is transmission-coupled to the section.