JPH0693035B2 - Fast breeder reactor spent fuel handling system - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a spent fuel for a fast breeder reactor, which transfers the washed fuel taken out from the reactor vessel of the fast breeder reactor through water to the underwater fuel storage tank side. Regarding the handling system.

[Technical background of the invention]

FIG. 3 shows an outline of a spent fuel handling system in a conventional fast breeder reactor.

Regarding the handling of spent fuel in the reactor vessel 1, the fuel burned sufficiently in the core 2 is moved to the in-core fuel storage rack 4 by the operation of the fuel exchanger 3 installed in the upper part of the reactor vessel 1, and next time Stored until refuel, reducing decay heat levels. The spent fuel, which has been stored in the in-core fuel storage rack 4 since the previous refueling and has the decay heat level lowered, is taken out of the reactor vessel 1 by the fuel inlet / outlet unit 5.

The spent fuel taken out by the fuel inlet / outlet unit 5 is once transferred to the outside-reactor relay tank 6 and immediately, in order to prevent the reaction of adhering sodium, a dry cell (a small chamber kept in an inert gas atmosphere) in which water is not taken in It is transferred to the rotary cleaning tank 8 by the in-cell crane 7. The rotary cleaning tank 8 is
In order to continuously wash the spent fuel sent one after another, the turntable is equipped with two washing tanks. After washing the received spent fuel, the turntable is turned over. And transfers it to the wet cell (small chamber in an air atmosphere containing water) provided with the submersible fuel storage tank 9, is transferred by the in-cell crane 10 in the wet cell, and is stored in the submersible fuel storage tank 9 to be reused. It specializes in shipping to processing plants.

When carrying out the spent fuel in the underwater fuel storage tank 9 to the reprocessing plant, several containers are housed in the cask container 11 and delivered to the cask carrier 13 using the cask container handling hoist 12 and then the overhead crane. It is loaded onto an unloading trailer 15 by 14 and is transported to a port facility or the like.

[Problems of background technology]

In the above system, the spent fuel washed in the rotary washing tank 8 is transferred by the in-cell crane 10 in the wet cell,
Once taken out into the gas atmosphere, it is transferred to the underwater fuel storage tank 9, so it is necessary to restrict the entry of the operator into the wet cell.

Further, since the rotary cleaning tank 8 in which two cleaning tanks are mounted on the turntable is used, much maintenance is required for the rotary joints of the supply / discharge pipes for the cleaning gas and cleaning water.

[Object of the Invention]

An object of the present invention is to use a spent fuel handling system for a fast breeder reactor, which can transfer spent fuel having decay heat after cleaning without removing it into a gas atmosphere and can shorten the maintenance period of the cleaning tank. To provide.

[Outline of Invention]

The present invention, after reducing the decay heat level by storing the spent fuel taken out from the core in the in-reactor fuel storage rack provided in the reactor vessel, taken out of the reactor vessel and washed, Furthermore, in the spent fuel handling system of the fast breeder reactor that is stored in the underwater fuel storage tank and then transported to the reprocessing plant, a cylindrical cleaning tank that stores and cleans the spent fuel taken out of the reactor vessel , A door valve for opening and closing the lower end of the cleaning tank, a water pool provided under the door valve, a fuel lifter for handling spent fuel in the cleaning tank above the cleaning tank, and a door valve for the cleaning tank through the door valve. An underwater transfer device for receiving the spent fuel discharged from the lower end in the water of the water pool and delivering it to the underwater fuel storage tank side, and a lower end of the spent fuel stored in the cleaning tank above the door valve. A support plate for supporting at position, characterized in that the spent fuel using the support plate after the completion of cleaning is moved in a horizontal direction; and a fuel supporting device to pass to the water transfer device.

Example of Invention

FIG. 1 and FIG. 2 show an embodiment of the present invention, in which the spent fuel taken out from the reactor vessel 1 through the refueling machine 3, the fuel loading / unloading machine 5 and the relay tank 6 outside the reactor is in the dry cell. Is transferred in the inert gas atmosphere by the in-cell crane 7 installed in the cell and is delivered to the fixed fuel cleaning device 16 installed under the cell floor for cleaning. Although only one fuel cleaning device 16 is shown in FIG. 1, this number can be determined according to the number of fuels to be handled and the handling schedule.

The spent fuel after the completion of the wet gas cleaning is delivered by the in-cell fuel lifter 17 to the submersible transfer device 18 arranged immediately below the fuel cleaning device 16, and is transferred into the water pool 19. After that, the spent fuel is transferred from the underwater transfer device 18 to the underwater fuel storage tank 9 by the pool transfer device 20 installed above the water pool 19, and is stored there until being transported to the reprocessing plant.

Further, the procedure for carrying out the spent fuel to the reprocessing plant is performed by the pool transfer machine 20 from the underwater fuel storage tank 9 to the cask container 11.
After being housed in the cask trolley 13 by using the container handling hoist 12 in the cask as before, it is loaded on the unloading trailer 15 by the overhead crane 14 and transported to the port facility.

FIG. 2 shows the details of the fuel cleaning device 16.

The spent fuel 21 to which sodium has been transferred, which has been transferred by the in-cell crane 7 in the dry cell, is stored in the cylindrical cleaning tank 23 via the door valve 22 on the cell floor side, and the fuel 21
The lower end of is supported by the fuel support device 24. At this time the washing tank
The water transfer chamber side door valve 25 located at the lower end of 23 is closed and isolated from the water pool 19 side.

In this state, cleaning with wet gas is performed, and thereafter, cleaning water is circulated through the cleaning water inlet 26 and the cleaning water outlet 27,
Wash the fuel 21.

After the cleaning is completed, the cleaning tank 23 is filled with clean water, the in-cell fuel lifter 17 traveling on the track is positioned on the cell floor side door valve 22, the fuel lifter door valve 28 is connected, and the gripper 29 of the fuel lifter 17 is used. The fuel 21 is grabbed and slightly lifted to a position where the support plate 33 of the fuel support device 24 can be moved.

The support plate 33 in the fuel support device 24 is movable in the horizontal direction, and when the fuel 21 is transferred to the submersible transfer device 18 after cleaning, the support plate 33 does not interfere with the descent of the fuel 21.
Is retracted into the casing 30 of the fuel support device 24. Therefore, the fuel 21 can be delivered to the submersible transfer device 18 by opening the submersible transfer chamber side door valve 25 and using the in-cell fuel lifter 17.

〔The invention's effect〕

According to the present invention, the spent fuel that has been cleaned is directly transferred from the cleaning tank 23 to the underwater transfer device 18 in the water pool 19, and the underwater transfer device 18 is horizontally moved in water to perform the underwater fuel storage tank 9
Since it can be delivered to the side, the forced gas cooling device from the underwater transfer device 18 to the delivery to the underwater fuel storage tank 9 side becomes unnecessary, and the number of forced gas cooling devices can be reduced. Further, since the horizontal transfer function of the cleaning tank 23 itself is unnecessary and the cleaning tank 23 can be fixed, the structure of the fuel cleaning device 16 can be simplified.
Further, since the present invention includes the fuel support device that supports the lower end of the spent fuel stored in the cleaning tank at a position above the door valve, the lower end of the spent fuel does not come into contact with the door valve. It is possible to prevent the spent fuel from being damaged by opening and closing.

[Brief description of drawings]

FIGS. 1 and 2 show an embodiment of the present invention. FIG. 1 is a schematic configuration diagram of a spent fuel handling system, FIG. 2 is a sectional view of a fuel cleaning device, and FIG. It is a schematic block diagram which shows a spent fuel handling system. 1 ... Reactor vessel, 2 ... Reactor core, 4 ... Reactor fuel storage rack, 9 ... Underwater fuel storage tank, 16 ... Fuel cleaning device, 17
...... Fuel lifter, 18 …… Submersible transfer device, 19 …… Water pool, 21 …… Spent fuel, 23 …… Wash tank, 24 …… Fuel support device, 25 …… Door valve, 33 …… Support plate.

Claims (1)

[Claims] 1. A spent fuel taken out of a reactor core is stored in an in-reactor fuel storage rack provided in a reactor vessel to reduce the decay heat level, and then taken out of the reactor vessel for cleaning. In the spent fuel handling system of the fast breeder reactor that is further stored in the underwater fuel storage tank and then transported to the reprocessing plant, a cylindrical cleaning tank that stores and cleans the spent fuel taken out of the reactor vessel. A door valve for opening and closing the lower end of the cleaning tank, a water pool provided under the door valve, a fuel elevator for handling spent fuel in the cleaning tank above the cleaning tank, and the cleaning tank through the door valve. An underwater transfer device for receiving the spent fuel discharged from the lower end of the underwater in the water pool and delivering it to the underwater fuel storage tank side, and the lower end of the spent fuel stored in the cleaning tank to the door valve. A fast breeder reactor having a support plate that supports the upper position, and a fuel support device that transfers the spent fuel to the submersible transfer device by moving the support plate in the horizontal direction after cleaning is completed. Spent fuel handling system.