JPS63150692A - Fuel exchanger for nuclear reactor - 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 [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 above-mentioned fuel exchange device.
In the figure, l is the reactor vessel that houses 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 off-cenotor arm installed on the rotating plug 4. It is a type fuel exchange device. Here, the fuel exchange device 5 has a drive part 41 at the top of the outside of the furnace, and a main shaft part 42 that penetrates the three-turn plug 3 and is inserted into the inside of the furnace.
It is comprised of a hold down tube 44 attached to the side of the main body shaft portion 42 via an offset arm 43, a gripper 45 that is moved up and down along the internal fuel passage of the hold down tube 44, and the like.

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

On the other hand, in addition to the fuel exchange device 5, an in-core relay device W6 is installed on the side of the reactor core 2 in the reactor vessel for carrying out the spent fuel extracted from the reactor core 2 and carrying new fuel into the reactor. Established! The fuel is transferred via the in-core relay device 6 to the fuel inlet/output machine 7, which is a fuel transfer equipment installed outside the reactor.
It is configured to perform reverse output. The shielding plug 3 has a fuel inlet/outlet passage 31. And its door valve 32 is provided. Here, the spent fuel extracted from the reactor core 2 is transferred 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, it is transferred to the in-core relay device 6, following the path shown by arrow A. is carried out of the furnace. On the other hand, contrary to the above, 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, fuel is received by the operation of the fuel exchange device 4 and transferred to the reactor core.
is loaded.

[Problem that the invention seeks to solve]

As mentioned above, conventional fuel exchange equipment requires the removal of fuel,
During the loading operation as well as the fuel transport process within the reactor, the fuel contained in the hold-down tube is suspended and gripped by the gripper from above.

Therefore, if the fuel exchange device 5 and the fuel inlet/outlet machine 7 try to directly transfer fuel when carrying in and out fuel, the gripper on the fuel exchange device side and the gripper on the fuel inlet/outlet machine side will be the same. They interfere with each other from both directions, making it impossible to transfer fuel. For this purpose, in the past, the in-core relay device 6 was installed inside the reactor vessel as described above, and when carrying in and out the fuel, the fuel was transferred to the gripper of the fuel exchange device or at the relay point of the in-core relay device 6. The fuel is transferred after being separated from the gripper of the fuel loading/unloading machine.

However, as mentioned above, inside the reactor vessel 1, the reactor core 2
Placing the in-core relay equipment W6 on the side of the reactor not only complicates the in-core structure accordingly.

The diameter of the reactor vessel 1 becomes larger, and the reactor containment vessel also becomes thicker (this results in an increase in the construction cost of the 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 Problem c] In order to solve the above problem, according to the present invention, a rotation avoidance mechanism that avoids the gripper to the top side of the holddown tube, and 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 to the side of the top of the holddown tube, It shall be equipped with a lower support for supporting fuel that can be accessed and removed from the side.

[Effect]

In the above configuration, the gripper is positioned at the center of the hold-down tube during fuel exchange.

With the lower support stand retracted out of the fuel passage, the gripper is moved up and down to carry out fuel loading and unloading operations with respect to the reactor core. On the other hand, when transporting fuel,
By avoiding rotation of the gripper to the side of the top of the hold-down tube and moving the hold-down tube to a position corresponding to the fuel transfer equipment outside the reactor with the lower support protruding into the fuel passage, the gripper and Fuel can be transferred directly between the fuel transfer equipment and the holddown tube without interference.

〔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 the present invention, first, the gripper 55 of the fuel exchange device 5 is attached to a ball cage installed on the lifting guide rail 8 which is parallel to the hold down tube 54 and supported by the offset arm 53 at a lateral position thereof. 9 are connected via a hexagonal nut 10, and the ball screw 9 is connected to a gear mechanism 11. It is transmission connected to a drive section 51 of the fuel exchange device 5 via a drive shaft 12 . Further, the guide rail 8 is supported by a bearing on an offset arm 53 so as to be able to rotate about its axis while supporting the gripper 55, and the guide rail 8 is supported by a gear mechanism 13 provided on its circumferential surface. It is transmission-coupled to the drive section 51 via the drive shaft 14 .

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 5
5 is rotated in the direction of arrow B together with the guide rail 8. 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 the 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 of the fuel passage from the rear in the direction of arrow C, and the lower support stand 56 is connected to the rear end as the operating mechanism. gear mechanism (not shown) 1
and is transmission-coupled via a drive shaft 15 to a drive section 51 of the fuel exchange device.

Next, the fuel costs for the transfer operation between the fuel transfer equipment outside the reactor and the fuel inlet/output machine of the above-mentioned configuration will be described with respect to the transfer operation and the fuel exchange operation performed between the reactor core and the reactor core. When bringing in new fuel from outside the reactor and loading it into the reactor core, first move the rotary plug 4. Then, the hold-down tube 54 is moved to a position directly below the fuel inlet/outlet 31 opened in the fixed plug 3 by a positioning operation by rotating the main body shaft portion 52 of the fuel exchange device. Then the first
As shown in the figure, raise the gripper 55 to the highest position and pull it out from the hold-down tube 54. Further, as shown in the figure, after protruding the lower support base 56 into the fuel passage in the hold-down tube, remove the guide rail 8 of the gripper. Rotation is performed to move the gripper 55 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 inside of the reactor through the fuel inlet/outlet 31 of the fixed plug 3, accommodated in the hold down tube 54 waiting just below it, and landed and supported on the lower support stand 56, after which the gripper of the fuel inlet/outlet machine 7 is suspended. 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.

As a result, the cost of transporting new fuel into the reactor is reduced by completing the transfer operation, and then lowering the gripper 55 to combine it with the fuel 16.Then, the fuel 16 is once raised together with the gripper, and the fuel passage is as shown in the figure. The rotation of the rotary plug 4 and the fuel exchange device 5 are performed by retracting the lower support base 56 from the fuel passage so as to invert the lower support base 56 that had been protruding into the vertical position.
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 main body shaft 52, and at this position, the gripper 55 is lowered to load the fuel 16 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 are removed. The hold-down tube 54 is accessed to a designated position on the core side by the rotational positioning operation of the tfA device 5, and the gripper 55 is operated here to extract the spent fuel from the core and collect it in the hold-down tube. The lower support 56 is operated to project into the fuel passage after the fuel 16 is raised to the highest level while being gripped by the lower support 56, and the gripper 55 is lowered again to cause the fuel 16 to land on the lower support 56. Subsequently, the gripper 55 is separated from the fuel 16, and the gripper 55 is removed again.
5 to the outside of the hold-down tube, and then rotate the guide rail 8 as shown in FIG. 2 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. Note that when transferring fuel between the hold down tube 54 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 that the rotation between the gripper 55 and the gripper 55 is avoided. The fuel 16 can be directly transferred between the fuel exchange bag W5 and the fuel inlet/outlet [7] without interference.

〔Effect of the invention〕

As described above, according to the present invention, there is provided a rotation avoidance mechanism that avoids the gripper to the side of the top of the hold-down tube, and a lower support for supporting fuel that is operated in and out of the fuel passage in the hold-down tube from the side. With the gripper positioned at the center of the hold-down tube and the lower support stand retracted out of the fuel passage, fuel exchange is performed between the core and the reactor core by raising and lowering 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: Core, 4: Rotating plug, 5: Fuel exchange device, 7: Fuel inlet/output machine for extra-core fuel transfer equipment, 8 Guide rail for Nigelipper, 9 Ball for lifting and lowering the Nigelipper. Gear mechanism of gripper rotation avoidance mechanism, 14
Drive shaft of nigeripper rotation avoidance mechanism, 51; Drive part of fuel exchange device, 52; Main body shaft part, 53: Offset arm,
54: Hold down tube, 55; Gripper, 56
: Lower support base. Mutual Fuel Lantern Xi Figure 1

Claims (1)

[Scope of Claims] 1) A nuclear reactor fuel exchange device that is installed on the upper rotating plug of a reactor vessel and performs fuel exchange with the reactor core, and is equipped with a drive section at the top and is mounted and supported on the rotating plug. a main body shaft, a hold-down tube supported on the side of the main body shaft through an offset arm, and a gripper that is operated up and down along the hold-down tube, wherein the gripper is held. It includes 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 in and out of the fuel passage in the hold down tube from the side, and positions the gripper 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. 1. A fuel exchange device for a nuclear reactor, characterized in that the fuel exchange device for a nuclear reactor is configured to directly transfer fuel between a fuel transfer facility outside the reactor and a hold-down tube in a state protruding 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.