JPS60174987A - How to transfer spent 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 [Field of Application of the Invention] The present invention relates to the removal and storage of fuel into spent fuel transport containers in light water nuclear power plants and independent spent fuel storage facilities, and particularly relates to the removal and storage of fuel into spent fuel transport containers in light water nuclear power plants and independent spent fuel storage facilities. The present invention relates to a spent fuel transport method suitable for a fuel transport cask.

[Background of the invention]

At nuclear power plants and reprocessing plants, spent fuel is temporarily stored in pools. As shown in Figure 1, spent fuel at nuclear power plants is transported out using the wet method, in which a transportation cask is submerged in a pool and the fuel is stored underwater after cooling for more than a year. As a result, the problem arises that the outer surface of the transport cask is contaminated with radioactive materials in the pool water, so it is necessary to decontaminate the outer surface of the transport cask with high-pressure jet water, or use the bagging method, in which the transport cask is covered with a plastic bag, or the transport cask is covered with metal. We have developed a technique for resist dyeing using the skirt method, which involves attaching a skirt made of plastic or a plastic bag and flowing fresh water between the skirt and the transport cask.

On the other hand, most reprocessing plants are facilities that extract fuel from transport casks using a wet method similar to nuclear power plants. Recently, a technique for extracting the material using a dry cell as shown in FIG. 2 has also been developed.

The wet method requires complicated handling for decontamination and anticontamination, and generates a large amount of waste. Furthermore, when handling the recently developed dry transportation and storage cask in a wet manner, the handling is complicated and takes a long time because water is removed and vacuum dried after storing the fuel.

The dry cell method requires a maintenance area above the cell so that equipment inside the dry cell can be repaired if it breaks down, as well as a crane for removal, which requires large-scale equipment and is difficult to install in a nuclear power plant. It was difficult to do so.

In the method disclosed in Japanese Unexamined Patent Publication No. 58-27478, as shown in FIG. 3, when fuel is taken out from a cask and stored, the fuel is temporarily stored. I had to take the water in and out of the pool. In other words, when moving fuel between a storage pool and a temporary pool, the temporary pool contains water, but when moving fuel between a cask and a temporary pool, the cask should not be contaminated with pool water. It is necessary to drain the pool water from the temporary pool. In addition, since fuel is transferred between the temporary pool and the cask under a horizontal shielding plate, the cask room becomes contaminated with scattered radioactive materials, which is contrary to its original purpose, and the cask itself becomes contaminated.Furthermore, the fuel transfer machine becomes contaminated. do. For this reason,
Repairs to fuel transfer equipment will be difficult.

[Purpose of the invention]

Spent fuel was originally supposed to be reprocessed, but for technical and economic reasons it is now considered that it will be put into interim storage. At that time, fuel that requires a long cooling period will be dry stored in dry casks or the like. Therefore, it is necessary to develop a spent fuel transport device that is simpler than conventional methods, can be installed at power plants, does not contaminate the cask, and does not require decontamination with high-pressure jet water, etc., except when repairing the interior. became.

[Summary of the invention]

Since the spent fuel is transported into and out of a dry cask, the wet method is not a good idea because it involves draining pool water, vacuum drying, etc. Therefore, we will use the dry method, but as with the dry cell method, we will move the multi-fuel feeder, which is frequently repaired, outside the dry cell. Therefore, the equipment for transferring highly radioactive fuel is equipped with a fuel storage tower that has a shielding function, and when moving from the dry cask to the temporary fuel storage pool, it is necessary to shield the radiation from the cask whose lid is removed. , the fuel transfer machine itself has a structure with a shielding plate.

When storing or taking out spent fuel in a dry cask, it is thought that radioactive crud will be scattered. Therefore, the fuel outlet of the dry cask is placed in close contact with the crud collection chamber, and the air in the crud collection chamber is removed using a high-performance filter using a blower. I decided to remove it because it was already sent to .

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 4 and 5. In addition, Fig. 4 is a plan view, and Fig. 5 is A-A on the plan view.
A cross section of the section is shown.

The overall configuration of the present invention is as follows.

A loading chamber 55 for dry casks 58 and the like is provided, and therein is provided a trolley 57 and rails 65 for transporting the casks 58 to the cask chamber 54.

The cask chamber 54 is equipped with a transfer device 60 for the cask lid 59, a rail 61, and a lifter 56 for bringing the cask into close contact with the radioactive material removal chamber 53.

A shielding wall of the radioactive material removal chamber 53 is provided with a high-performance filter 63 that filters air containing radioactive material scattered in the radioactive material removal chamber 53 and a blower 62 that blows the air to the filter.

At the top of the radioactive material removal chamber 53, a fuel transfer device 6 is provided to transfer the fuel.
A shutter 66 and a moving mechanism 67 are provided, which are closed except when moving to 4.

A temporary fuel storage pool 51 is provided in the cask chamber 54 across a wall, and a temporary fuel storage rack 52 is provided therein. It is assumed that the temporary fuel storage pool is adjacent to the fuel storage pool 5°.

It is composed of a fuel transfer machine equipped with a shielded fuel storage container 64 and a shield plate 65 that can move between the temporary fuel storage pool 51 and the cask chamber 54, and a rail 53.

Next, the operation of the present invention will be explained. First, a method for transporting fuel from the storage pool 50 will be explained. The empty cask is suspended from a cart 57 into the loading room 55 by an overhead crane. The bolts on the lid of the empty cask are removed, and the cart 57 is moved to the cask chamber 54 on the rails 65. The cask lid 59 is removed and moved to a predetermined position on the rail 61 by the cask lid transfer machine 6o.

The cask 58 with the lid 59 removed has a lid along with the trolley 57.
56, before the fuel is stored in the cask 58, it is raised to the radioactive material removal chamber 53 and brought into close contact with the cask chamber, and is isolated in the cask chamber. prevent contamination of equipment. At this time shutter 66
is assumed to be stopped.

The radioactive material removal chamber 53 is connected to a high-performance filter 63 for removing radioactive cladding and the like and a blower [62] for blowing air containing the radioactive cladding, thereby removing the radioactive material while recirculating the air. A part of the air is discharged to the ventilation air conditioning equipment 68 to remove radioactive materials from the radioactive material removal chamber 53.
This prevents air from coming out into the pool room 69.

With the above steps, the preparation for storing fuel in the cask is completed. Next, the fuel in the storage pool 5o is transferred to and stored in a temporary fuel storage rack by a fuel exchanger conventionally provided in the storage pool. The fuel transfer device 64 with the shield plate 65 is moved to the temporary pool 51 and the fuel is lifted from the temporary rack 52 into the fuel storage container 64 with the shield. After thoroughly draining the water, close the lower part of the fuel storage container 64 with a shield and open the fuel storage container 6.
4 is moved to the upper part of the cask chamber 54 on the rail 53.

After confirming that the blower 62 is functioning, the shutter 66 above the radioactive material removal chamber 53 is opened. Next, the lower part of the fuel storage container 64 is opened and the fuel is suspended in the cask 58.

When a predetermined amount of fuel is stored in the cask 58, the cask is lowered by the lifter 56. A cask lid 59 is transferred to the upper part of the cask 58 by a lid transfer machine 60. Trolley 5
7 is moved to the carry-in room 55 on the rail 65. Next, the cask lid 59 is bolted to securely secure it to the cask. The cask will then be removed using an overhead crane.

When transporting fuel from the cask to the storage pool 50, the procedure is reversed. That is, the cask containing fuel is suspended onto the trolley 57 in the loading chamber 55 by an overhead crane. After removing the bolts of the cask lid in the carrying-in room 54, the cask together with the cart 57 is moved to the cask room 54. After confirming that the shutter 66 above the radioactive material removal chamber 53 is closed and the blower 62 is operating, the cask lid 59 is removed by the cask lid transfer device 60. Next, the lifter 56 brings the cask and the cart into close contact with the radioactive material removal chamber 53. Open the bottom of the fuel storage container and lift the fuel from the cask. When the lifting is finished, remove the shirt f
During the period when i-66 is closed, the radioactive crud attached to the fuel is most likely to scatter, so the ventilation air conditioning system 68 is constantly operated to prevent the air in the radioactive material removal chamber 53 from flowing into the pool room 69. exhaust to. The air to be exhausted shall be sufficiently filtered by the direct performance filter 63.

After the lifted fuel closes the lower part of the fuel storage container 64, it moves to the upper part of the temporary rack 52 and is suspended on the temporary rack 53.

At this time, if fuel remains in the cask, radiation will leak from the opening at the top of the radioactive material removal chamber 53, so a shielding plate 65 is also attached to the fuel storage container 64 to shield the radiation.

The fuel in the temporary rack 52 is transferred to and stored in the storage pool 50 by a conventional fuel exchanger.

Since the radioactive material removal chamber is connected to the cask opening, it is possible to prevent radioactive materials from scattering, and it is economical because there is no maintenance cell installed at the top like in the dry cell method.

〔Effect of the invention〕

According to the present invention, it is possible to prevent the generation of large amounts of decontaminated water and radioactive waste such as rags, which would be generated by decontamination and anticontamination using the wet fuel transport method. Furthermore, since there is no need to drain the pool water in Cask C or vacuum dry it, the operation is simple and the operation time can be shortened.

In the present invention, when the cask is opened, by connecting the cask to a radioactive waste removal chamber, radioactive crud that is scattered during fuel handling is removed by filtering it with a high-performance filter while recirculating the air in the same chamber. By exhausting some of the leftover air to the ventilation air conditioning system, a flow of air is created from the pool room and cask room to the radioactive waste removal room, thereby preventing areas other than the radioactive waste removal room from being contaminated with radioactive materials. can. Therefore, it is easy for people to enter the casting room, and the lifter, lid transfer device, etc. can be maintained as usual. In addition, since the outside of the fuel storage container is not contaminated and the operating parts that are prone to failure can be maintained as usual, there is no need to provide a maintenance cell and equipment above as in the dry cell method, which is economical.

[Brief explanation of drawings]

Figure 1 is an illustration of the wet cell method used in conventional nuclear power plants, Figure 2 is an illustration of the dry cell method used in reprocessing facilities, and Figure 3 is an explanation of the dry fuel loading/unloading method. FIG. 4 is a plan view of the present invention, and FIG. 5 is a sectional view of the present invention. ■・・・Spent fuel storage pools at nuclear power plants, etc., 2.
...Cask, 3...Basket, F...Fuel, 1
0... Spent fuel storage pool, 11... Spent fuel storage pool transfer equipment, 12... Shielding body, 13...
・Shielding wall. 14... Water supply and drainage system storage cell, 15... Temporary fuel storage cell, 16... Cask storage cell, 17...
Shielding wall, 18... Shielding wall, 19... Temporary fuel rack, 20... Gate, 21... Gate, 22... Horizontal shielding plate, 23... Remotely operated crane, 24...・Cask, 30... Spent fuel storage pool, 31...
fuel storage rack. 32... Cask, 33... Dry cell, 34...
Fuel transfer machine, 35...Maintenance cell, 36...
Maintenance crane, 50... Spent fuel storage pool, 51... Temporary fuel storage pool, 52... Temporary fuel storage rack, 53... Radioactive material removal room, 54... Cask room, 55... - Loading room, 56... Lifter, 57.
... Trolley, 58... Cask, 59... Cask lid, 60... Lid transfer machine, 61... Rail, 62...
Blower, 63... High performance filter, 64... Fuel storage container, 65... Shielding plate, 66... Shaster, 67
...Shuster opening/closing machine, 68...Ventilation air conditioning system. Agent Patent attorney Akio Takahashi (mouth is also 20 7z #30

Claims (1)

[Claims] 1. A temporary fuel storage pool is provided adjacent to the spent fuel storage pool, and a temporary storage rack submerged in the pool water is provided therein,
A cask room is provided adjacent to the temporary fuel storage pool, separated by a shielding wall, and equipped with a radioactive material removal chamber at the top.The cask room is equipped with a cask lid transfer machine and a lifter to raise and lower the cask. A cask loading room is installed connected to the cask, which is equipped with a cart and rails for transporting the cask, and the upper part of the cask room and the temporary fuel pool are used to store fuel while shielding radiation from the fuel inside the cask. A use characterized in that a radioactive material removal chamber is provided in the upper part of the cask chamber in equipment planted from a movable fuel transfer device, so that spent fuel can be removed from the cask or radioactive crud generated during storage can be removed. How to transfer spent fuel. 2. In claim 1, a fuel storage container equipped with a shielding function capable of shielding radiation from spent fuel is moved from the top of a cask that contains spent fuel and does not have a lid to the cask to a temporary fuel storage rack. A method for transferring spent fuel, characterized in that a shielding plate is attached to the fuel storage container having a shielding function to prevent radiation from the cask from entering the pool room.