JPS6319035B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention provides a system for transmitting fuel through a fuel cleaning device while maintaining a vertically suspended position between a fuel inlet/output machine in a liquid metal sodium cooled nuclear reactor and a fuel transfer machine running in a fuel storage pool. This invention relates to improvements to nuclear reactor fuel transfer equipment that transfers fuel.

In the nuclear reactor mentioned above, a fuel storage pool is installed to cool and store a large number of fuels for a long period of time until the level of decay heat possessed by the spent fuel extracted from the reactor core is sufficiently reduced. On the other hand, spent fuel drawn from a nuclear reactor or an ex-core fuel storage tank that uses sodium as a coolant still has sodium adhering to its surface, so it is necessary to clean the sodium before drawing it into the fuel storage pool. be. A cleaning device for cleaning such fuel is installed in the middle of the transfer route before it is drawn into the pool, but in this case, the fuel before cleaning and the fuel after cleaning are handled by being stored in the same transfer container. This must be avoided. From the standpoint of radiation control, it goes without saying that the fuel must be brought into the pool through an externally shielded area.

Next, FIG. 1 shows a conventional fuel transfer facility constructed based on the above requirements. In the figure, 1
1 is a fuel loading/unloading machine that transfers fuel into and out of a nuclear reactor or sodium-cooled fuel storage tank.
Reference characters a and 1b are fuel storage containers mounted on the running carts of the fuel handling equipment, and the fuel handling equipment runs on rails laid on the floor along the fuel transfer route inside the fuel handling building. do. Reference numeral 2 denotes a fuel storage pool, and a fuel storage rack 3 that accommodates a large number of fuels is installed at the underwater bottom of the pool, and the hanging and unloading of fuel to and from this rack is carried out by a pool that runs through the pool. This is done by the fuel transfer machine 4. Reference numeral 5 denotes a fuel cleaning device, which is installed under the poolside floor in alignment with the travel path of the fuel inlet/outlet device 1. 5a
is the door valve. In addition, a fuel guide pipe 6 with a door valve is provided so as to vertically penetrate the floor surface of the poolside in line with the above-mentioned cleaning device, and whose lower end opens toward the side hole 2a of the pool formed below the water surface of the pool. It is being Furthermore, the pool receives fuel suspended from the fuel inlet/output machine 1 through the guide pipe 6, and the pool fuel transfer machine 4
An underwater fuel transfer device 7 is provided to transfer the fuel underwater to the delivery position. 7a is the running rail.

The sodium-adhered fuel drawn out from the reactor side with the above configuration is stored in one of the co-fins 1a of the fuel inlet/output machine 1, and transferred to the pool side, where it is transferred from the co-fin 1a to the fuel cleaning device 5.
The attached sodium is washed away by lowering the vessel to a vessel. After cleaning, the fuel is lifted into the other co-fin 1b which is free from sodium contamination, and when the fuel inlet/output machine 1 is moved to the position of the guide pipe 6, it is lowered through the guide pipe 6 to the submersible fuel transfer machine 7. Here, it is separated from the fuel inlet/output machine 1, and then the underwater fuel transfer machine 7 is moved to the left and the pool fuel transfer machine 4 is moved to the left.
and finally stored in the underwater storage rack 3. During the entire transfer process, the fuel remains suspended in a vertical position. Also, since the fuel is drawn into the pool water from the fuel via the guide pipe, there is no radiation leakage to the outside.

However, in the conventional equipment described above, before the fuel is drawn into the pool, in order to transfer the cleaned fuel to the guide pipe 6 that opens on the floor above the pool water level, it is necessary to first transfer the cleaned fuel from the cleaning device 5 to the floor. It must be pulled upwards. Moreover, since the fuel before cleaning and the fuel after cleaning must be handled separately, the fuel inlet/output machine 1 requires two independent cofins 1a and 1b. Incidentally, the co-fins that house spent fuel are extremely heavy due to radiation exposure and are expensive to manufacture. For this reason, as shown in the figure, two
In addition to the economic disadvantage of being expensive, a fuel inlet/outlet machine configured by mounting several Cofins on a tower has a large weight, which makes it difficult to obtain sufficient earthquake resistance including the traveling truck. This is also disadvantageous from an earthquake-resistant design perspective.

This invention was made in consideration of the above points, and its purpose is to improve the conventional equipment and create an advantageous fuel transfer equipment that is more economical and has fewer problems with earthquake resistance as a fuel inlet/output machine. It is about providing.

The present invention will be described in detail below based on illustrated embodiments.

In FIG. 2, the same reference numerals as in FIG. 1 indicate the same members. The illustrated fuel inlet/outlet machine 1 differs from that shown in FIG. 1 in that only one fuel inlet/outlet machine 1 is mounted on the tower. Further, a relay cell 8 used for fuel transfer relay is formed under the floor surface of the pool side in alignment with the traveling route of the fuel inlet/outlet machine 1. The relay cell 8 has an upper fuel passage 9 that penetrates the ceiling and opens to the running floor surface of the fuel inlet/outlet machine 1, and an upper fuel passage 9 that penetrates the floor surface of the relay cell 8 and opens below the water surface in the pool. A fuel cleaning device 5 is provided, which is positioned directly below the lower fuel passage 10 and the upper fuel passage 5, and is installed under the floor of the relay cell. The lower fuel passage 10 is provided with a door valve 11 at its upper end, and a watertight connection mechanism 12 at its lower end for watertight connection with an underwater fuel transfer device to be described later. Furthermore, a relay cell fuel transfer device 13 is provided inside the relay cell 8 to transfer fuel between the cleaning device 5 and the lower fuel passage 10. As shown in the figure, this transfer device 13 may be of a traveling trolley type that travels on a traveling rail 13a, or may be a so-called transfer rotor, in which fuel is suspended at the tip of a rotating arm that rotates on a horizontal plane. A transporter having a structure equipped with a mechanism may also be adopted.

Next, the fuel transfer operation by the fuel transfer equipment having the above configuration will be explained step by step. The fuel stored in the co-fin 1a of the fuel inlet/outlet machine 1 and transferred is first connected to the door valve of the upper fuel passage 9, and then suspended through the passage 9 into the cleaning device 5 located directly below. be descended. After cleaning here, it is then lifted up by a transfer device 13 in the relay cell and transferred to the lower fuel passage 10. On the other hand, in the pool, the underwater fuel transfer device 7 runs to just below the fuel passage 10,
Further, the fuel storage cylinder is connected to the watertight connection mechanism 12 and is on standby. In this state, the door valve 11 is opened and fuel is delivered to the underwater fuel transfer device 7 through the fuel passage 10. In this process, even if the door valve 11 is opened, water from the pool will not enter the relay cell. Next, the door valve 11 is closed after separating the fuel from the fuel machine 13 of the relay cell. Thereafter, the underwater fuel transfer device 7 and the connection mechanism 12 are separated, and the transfer device 7 is moved to the left, whereupon the fuel is transferred to the pool fuel transfer device 4, and finally it is lowered to a predetermined position in the fuel storage rack 3. accommodate. Note that the relay cell 8 is isolated from the outside by a door valve 9a of the upper fuel passage 9, and therefore the transfer machine 13 installed in the relay cell is a type such as the Cofin 1a mounted on the fuel intake/discharge machine 1. A cage structure is not necessary at all, and it can be configured as a simple transfer device simply equipped with a fuel lifting mechanism and a fuel cooling device.

As described above, this invention provides a fuel relay cell under the floor of the poolside, is equipped with a fuel cleaning device so that fuel can be directly lowered from the fuel inlet/output machine through the fuel passage, and In order to transfer fuel to the underwater fuel transfer machine running inside the fuel storage pool, a connection mechanism that can be watertightly connected to the underwater transfer machine is provided in the fuel passage that penetrates the floor of the relay cell, and the relay cell A relay cell fuel transfer device is installed within the tank to transfer fuel from the fuel washing device to the underwater transfer device through the fuel passage. Therefore, when the fuel transferred from the fuel inlet/output machine to the fuel cleaning device is drawn into the pool after sodium cleaning, it is no longer necessary to temporarily lift it above the water level of the pool as in the conventional equipment shown in Fig. 1. It can be directly drawn into the pool via a relay cell under the floor. This eliminates the need for the fuel inlet/outlet machine to have two Cofin towers, unlike conventional equipment, which not only greatly reduces manufacturing costs, but also has advantages in terms of earthquake resistance. In addition, compared to conventional equipment, the degree of freedom in arranging the equipment as a whole is increased, so there is an advantage that the layout of the fuel transfer equipment within the limited fuel handling building is easier.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams of a conventional fuel transfer facility and an embodiment of the present invention, respectively. DESCRIPTION OF SYMBOLS 1...Fuel entry/exit machine, 2...Fuel storage pool, 4...Pool fuel transfer device, 5...Fuel cleaning device, 7...Underwater fuel transfer device, 8...Relay cell, 9...Upper fuel passage, 1
0...Lower fuel passage, 12...Watertight connection mechanism, 13...
Relay cell fuel transfer machine.

Claims (1)

[Claims] 1. Fuel is transferred while maintaining a vertical position between the fuel inlet/output machine that runs on the floor along the fuel transfer route between the reactor side and the fuel storage pool and the pool fuel transfer machine that runs in the fuel storage pool section. Reactor fuel transfer equipment that transfers fuel via a cleaning device, and a relay cell formed under the floor of the pool side aligned with the travel path of the fuel inlet/outlet machine;
An upper fuel passage formed to penetrate the ceiling of the relay cell and open to the running floor of the fuel inlet/outlet machine, and a fuel cleaning device installed under the floor of the relay cell aligned directly below the upper fuel passage. and a lower fuel passage formed to penetrate the floor of the relay cell and open below the water surface in the fuel storage pool, and a lower fuel passage formed in the relay cell to transfer fuel between the fuel cleaning device and the lower fuel passage. The relay cell fuel transfer machine installed in the pool, and the underwater fuel transfer machine installed in the pool so as to travel underwater in the pool and transfer fuel between the relay cell fuel transfer machine and the pool fuel transfer machine through the lower fuel passage. A nuclear reactor fuel transfer facility comprising: a fuel transfer device; and a watertight connection mechanism that connects the underwater fuel transfer device and a lower fuel passage in a watertight manner.