JPS6138836B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel transfer device for handling and transferring spent fuel in an underwater spent fuel storage facility for a nuclear reactor.

As is well known, spent fuel extracted from a reactor core is sealed in a sealed can and then submerged in an underwater storage rack installed in a water pool of an underwater storage facility for cooling storage. In this case, a fuel transfer machine is used to handle and transfer the sealed can containing the spent fuel (hereinafter simply referred to as "fuel") within the water pool.
An overview of such a fuel transfer device and underwater storage facility is shown in FIG. In the figure, a fuel storage pool 3 1 filled with water 2 used as a cooling medium and a radiation shielding material is a fuel storage rack installed within the pool 1 . On the other hand, the fuel transfer device 4 includes a cart 5 that runs on a running rail laid along the poolside,
It is composed of a traversing truck 6, a gripper 7, a gripper lifting/lowering drive device 8, a guide tube 9 for guiding the gripper 7 in lifting/lowering, and the like. Reference numeral 10 is a sealed can containing fuel suspended from the gripper 7, and H is a predetermined water surface level in the water pool.

By the way, when handling the sealed can 10 containing fuel in the water pool 1, the sealed can 10 should be handled from the viewpoint of radiation control.
It is necessary to always maintain the container at a predetermined depth or higher below the water surface, which is a radiation-resistant material.However, when the fuel transfer device 4 grabs the sealed can 10 and transfers it underwater, it is necessary to operate the gripper lifting drive device. Due to a mistake or the like, there is a risk of an erroneous operation in which the sealed can 10 is lifted to a water depth level shallower than the allowable water depth.
From this point, the fuel-containing sealed can 1, which is the object to be transferred,
In other words, it is desirable to regulate the upper limit of the upward stroke of the gripper 7 with the sealed can hanging thereon, and to take some kind of upper limit regulating means to prevent it from rising any further.

As such a means, attempts have been made to limit the upper limit of the gripper stroke by electrically interlocking the gripper lifting/lowering drive device, but this method has low reliability because it lacks a mechanical back-up mechanism. It is also conceivable to provide a fixed stopper in the middle of the gripper's lifting path as a mechanical upper limit mechanism, but in this case, the gripper must be immediately pulled out of the water even when the gripper requires maintenance inspection. It is difficult to maintain because it cannot be done.

The present invention has been made in consideration of the above points, and its purpose is to mechanically limit the upper limit of the upward movement of the gripper during operation, while also taking into account the maintainability of the gripper, to maintain the sealed can at a predetermined water depth level or higher. The objective is to obtain a fuel transfer machine that can

According to the present invention, the gripper guide tube is provided with a stopper, and by operating the stopper between the operating position and the release position, the upper limit of the stroke of the gripper is set so as to maintain the sealed can suspended from the gripper at a predetermined water depth level or higher. This is achieved through regulation or deregulation.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In FIGS. 2 and 3, the gripper guide tube 9 is equipped with a mechanical stopper mechanism 11 according to the invention. This stopper mechanism 11 is constructed as a combination mechanism of a stopper piece 12, an operating handle 13, and an operating shaft 14 connecting the stopper piece 12 and the operating handle 13. Note that 15 is a supporting outer cylinder of the guide tube 9. Among the above-mentioned parts, first, the stopper piece 12 is placed at the upper limit position of the upward movement stroke of the gripper 7, which is determined based on the predetermined water depth level mentioned above, and the stopper piece 12 is inserted into the guide tube through a slit cut in the middle of the guide tube 9 toward the pipe line inside the guide tube. It consists of two rotating partition plates that can be moved in and out from either side. On the other hand, the operating handle 13 is installed at an operating end position on the traveling truck of the fuel transfer machine so that maintenance personnel can directly operate it manually. With this configuration, when the operating handle 13 is rotated, the stopper piece 12 is moved between the release position indicated by the solid line and the actuation position indicated by the chain line via the operating shaft 14, as shown in FIG.
It is rotated like this. That is, if the gripper 7 is sufficiently lowered and the handle is operated to move the stopper piece 12 to the operating position indicated by the chain line, the upper limit of the upward stroke of the gripper 7 will be regulated by the stopper piece 12, and the gripper 7 that is being handled will be Sealed can 1
0 will be held underwater to maintain a predetermined water depth level. When maintenance and inspection of the gripper 7 is performed as necessary, the stopper piece 12 is switched to the release position indicated by the solid line by operating the handle. Therefore, the pipe partition of the guide pipe 9 is eliminated, and the gripper 7 is removed by its winding drum 81 in the gripper lifting/lowering drive device 8.
By winding up the chain suspending the gripper 7, the gripper 7 passes through the stopper piece 12 from underwater and is pulled up to the inspection position shown by the chain line 7', and maintenance work can be performed at this position.

In the illustrated example, the stopper piece 12 is made up of two pieces, but it may be made up of one piece, and the operation handle 13 can be operated by a manual type or a power operated type. You can also do that.

By being equipped with the above-mentioned mechanical stopper mechanism and using it alone or as a backup mechanism with electrical interlock control of the gripper,
When a sealed can containing spent fuel is handled and transferred under the water surface of a water pool in an underwater storage facility, it is possible to reliably prevent the sealed can from erroneously rising above a predetermined water depth level. Furthermore, when performing maintenance on the gripper, by switching the stopper mechanism to the release position, it is possible to immediately raise it from the water to the inspection position.The present invention makes it possible to provide a fuel transfer device with high practical value. can.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing the fuel handling state in the underwater storage facility of the fuel transfer device that is the subject of the present invention, Fig. 2 is a configuration diagram of the main parts of the embodiment of the present invention, and Fig. 3 is the diagram shown in Fig. 2. FIG. 1...Water pool of underwater storage facility, 2...Water, 3
...Fuel storage rack, 4...Fuel transfer machine, 5...
Traveling trolley, 7...Gripper, 8...Gripper lifting drive device, 9...Gripper guide pipe, 10...Sealed can containing spent fuel, 11...Stopper mechanism, 12
...Stopper piece, 13...Operation handle, 14...
...Operation axis, A...Operation direction of the stopper piece.

Claims (1)

[Claims] 1 Consists of a gripper, a gripper elevating drive device, and a gripper guide pipe mounted on a traveling trolley, and used to handle and transport sealed cans containing spent fuel while immersed in water in a water pool of an underwater storage facility by operating the grippers. In this fuel transfer machine, a stopper piece that can be moved in and out from the side toward the inside of the pipe line as if to partition the middle part of the gripper guide pipe, an operating handle provided at the operating end position on the traveling truck, and the stopper piece and the operating handle are provided. A stopper consisting of an operating shaft connecting the gripper is provided, and by operating the stopper to the operating position or release position, the stroke of the gripper is controlled so as to keep the sealed can suspended from the gripper at a predetermined water depth level or higher. A fuel transfer device used in a nuclear reactor fuel underwater storage facility characterized by regulating or releasing the upper limit.