JPS61280598A - Gripper for handling reactor fuel - 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] [Technical field to which the invention pertains]

The present invention relates to the configuration of a nuclear reactor fuel handling facility, such as a gripper for handling nuclear fuel, which is suspended into a spent fuel storage pool and handles the fuel by remote control from outside the pool.

[Prior art and its problems]

As this type of fuel handling gripper, a structure shown in FIG. 3 has been put to practical use and is well known. In FIG. 3, reference numeral 1 denotes a casing of a gripper that is suspended and supported by a crane or the like by a wire row 12, and this casing 1 has a swinging type gripper with a claw tip protruding from the bottom side of the casing to grip a handling head 3 on the fuel side. a claw 4 (only one claw is shown in the drawing, but normally three claws are arranged around the circumference), an actuator 5 that controls opening and closing of the claw 4, and an actuator 5 that controls opening and closing of the claw 4; 4, a plunger-type electromagnet 6 as a drive unit for opening the actuator 5, an operating shaft 7 that connects the plunger 6a of the electromagnet 6 and the actuator 5, a spring receiver 8 installed in the middle of the operating shaft 7, and a spring receiver 8. The gripper is constructed by incorporating main components such as a compression spring 9 for restraining the closed position of the claw 4 interposed between the gripper and the casing side. Note: 0 is the claw 4
11 is an auxiliary link for opening the claw 4, 1
2 is a bearing of the operating shaft 7; 13 is a bellows for water sealing installed between the operating shaft 7 and the partition wall on the casing side so as to isolate the claw side and the electromagnet side within the casing;
A power supply cable 14 connects the electromagnet 6 and an external power source. The operation of the gripper with the above configuration is well known, and the illustration shows that the gripper is connected to the handling head 3 on the fuel side.
It shows that the person is grasping the . In this state, the electromagnet 6 is not energized, and the actuator 5 is pushed down by the bias of the spring 9, restraining the claw 4 in the closed position. When separating the fuel from the gripper, first lower the gripper by letting out the wire rope 2, suspend the fuel to a predetermined position, for example, in a fuel storage pool, and then 1! The magnet 6 is energized and excited to attract the plunger 6a, and the actuator 5 is raised against the spring 9. As a result, the claw 4 swings clockwise around the bottle 10 via the auxiliary link 11 to open and detach from the handling head 4. On the other hand, when newly grasping fuel, the gripper is moved to a position directly above the fuel and lowered, and then the electromagnet 6 is energized and the claws 4 are opened.
After confirming that the Tift stone 6 faces the handling head 3 on the fuel side, the power to the Tift stone 6 is turned off. This causes spring 9
The actuator 5 descends and closes the claw 4 due to the bias of
The handle head 3 is now gripped. As mentioned above, this type of gripper uses a spring 9 to restrain the gripper claws in the closed position in order to prevent the fuel from accidentally falling off the gripper during lifting and transfer of the fuel number.
The electromagnet 6 or its tiff which is the driving part of the gripper
The gripper claws are configured as a non-excitation operated type to prevent the gripper claws from opening unexpectedly even if a failure occurs in the system. However, with such a non-excitation operating method, while it is possible to prevent the occurrence of fuel dropping accidents, it is possible to prevent the occurrence of fuel dropping accidents.
In the unlikely event that a failure occurs in the tti stone or its power supply system, the claws 4 will no longer be able to be opened, making it impossible to separate the gripper from the fuel, which will impede the fuel handling process. become. Moreover, when handling fuel in a spent fuel storage pool with a gripper, it is impossible to lift the gripper to the poolside while holding the fuel and repair it because the fuel has a high level of decay heat. It is Noh.

[Purpose of the invention]

This invention has been developed in consideration of the above points, and even in the event of an emergency situation in which a failure occurs in the drive section for opening the gripper's claws while the gripper is gripping fuel, it is possible to To provide a gripper whose claws can be easily opened by manual operation using a jig to separate the gripper from fuel.

[Key points of the invention]

In order to achieve the above object, the present invention provides a release lever mechanism in the casing of the gripper that forcibly moves the actuator toward the claw release position by manual operation from the outside. If the drive unit for opening the gripper's claws breaks down while handling the gripper, the claws can be opened by manually operating the release lever from outside the pool using an appropriate jig. This allows the fuel and gripper to be easily separated.

[Embodiments of the invention]

1 and 2 show an embodiment of the invention, and the same parts corresponding to FIG. 3 are given the same reference numerals. That is, according to the present invention, a release lever mechanism designated by the reference numeral 15 is newly added to the above-mentioned gripper. This release lever mechanism 15 is made up of a combination of a release lever 16 that is vertically and separately arranged on the outer peripheral surface of the casing 1, and a backward biasing spring 17 that always retracts and holds the release lever 16 in a non-operating position. Here, the aforementioned release lever 16
The hook part at the lower end is located opposite to the lower side of the spring receiver 8 arranged in the casing through the long groove window 1a opened in the side surface of the casing 1, and the upper end is positioned opposite to the spring receiver 8 provided in the casing 1.
It extends above the top of the ring and is connected to a control end ring designated by 18. On the other hand, the backward biasing spring 17 is compressed within the casing between the release lever 16 and the wall surface on the casing side so as to always push and bias the release lever 16 downward so as not to interfere with the spring receiver 8. It has been assisted. Next, the operation of the above-mentioned structure will be explained. Figure 0 shows a normal operating state in which the release lever mechanism 15 is in the inoperative position and the gripper is gripping the fuel. Here, if the gripper functions normally, the i!
By energizing and energizing the electromagnet, the claws 4 can be opened by remote control to separate the handling head 3 on the fuel side and the gripper. In this state, the release lever 16 is retracted downward by the spring force of the retraction biasing spring 17, so it does not interfere with the claw opening/closing drive system and does not interfere with the normal opening/closing operation of the gripper. On the other hand, if a failure occurs in the magnet 6 or its source system while the gripper is gripping the fuel, and it becomes impossible to disconnect the fuel using the remote control method, the fuel can be removed from the pool. After transporting it to the specified position and lowering it, the maintenance staff uses a jig such as a long operating rod with a hook attached to the tip from the pool side and lowers it to the gripper position by relying on the wire rope 2, and then releases it as described above. A jig is hooked onto the operating end ring 18 of the lever mechanism, and the release lever 16 is pulled upward. As a result, the release lever 16 rises, and its lower tip hits the lower surface of the spring receiver 8 inside the casing, forcing the actuator 5 to move upward together with the spring receiver 8 via the operating shaft 7. As a result, nail 4
is opened and separated from the handling head 3 on the fuel side. Note that when the release lever 16 is pulled up, the casing 1
If there is a possibility that the gripper casing 1 may rise together with the gripper casing, the release lever 16 can be raised relative to the casing by pressing the head of the gripper casing 1 from above using another jig.

【Effect of the invention】

As described above, according to the present invention, the gripper casing is provided with a release lever mechanism that forcibly moves the actuator toward the claw release position by manual operation from the outside, so that the gripper grasps the fuel. Even in an emergency situation where the drive part for opening the gripper breaks down and it becomes impossible to separate the gripper from the fuel using the remote control method, the release lever mechanism can be operated from the outside using a jig. By operating the gripper, the claws can be manually opened to separate the gripper from the fuel, thereby improving the reliability of the gripper.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the configuration of a gripper for handling nuclear fuel according to an embodiment of the present invention, and FIG.
The n cross-sectional view and FIG. 3 are vertical cross-sectional views of a conventional gripper. In the figure, 1: the casing of the nigerippa, 2: the wire rope, 3: the handling head on the fuel side, 4: the claw that grips the handling head, 5: the actuator, 6
: Electromagnet as a drive unit for opening the claw, 6a: Electromagnetic plunger, 9: Spring for restraining the claw in the closed position, 15: Release lever mechanism, 16: Release lever, 17: Retreat biasing spring.

Claims (1)

[Scope of Claims] 1) A claw that grips the handling head on the fuel side on the casing of the gripper suspended and supported by a wire rope, an actuator that controls opening and closing of the claw, a drive unit connected to the actuator for opening the claw, etc. In a reactor fuel handling gripper that is equipped with a built-in gripper and handles fuel by opening and closing the claws by remote control, the actuator is forcibly directed to the claw open position by manual operation from the outside of the casing. A gripper for handling nuclear reactor fuel, characterized by being provided with a release lever mechanism for moving operation. 2) In the gripper according to claim 1, the release lever mechanism is a release lever disposed such that the tip thereof faces the drive system member of the actuator within the casing and the upper operating end faces the outer circumference of the top of the casing. 1. A gripper for handling nuclear fuel, comprising: and a backward biasing spring that normally holds the release lever in an inoperative position.