JPS63122995A - Refrigerant injector for fuel canned can - 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 a cooling medium injection device for a fuel can that is filled with a cooling medium to store nuclear reactor fuel, particularly spent fuel, and seals the upper end opening. Regarding.

[Prior art and its problems]

Nuclear Reactor 1 For example, spent fuel taken out from a nuclear reactor, such as in a fast breeder reactor, is stored in cans and temporarily stored in a nuclear reactor facility, and then the cans are stored in a fuel transporter as needed. and sent to a reprocessing facility.

The above-mentioned canned can has a structure consisting of a cylindrical body and a lid that seals the upper opening of the can, and the spent fuel that has been cleaned is stored inside the body and cooled as a cooling medium until the liquid level reaches a certain level. Filled with water. In this case, the predetermined liquid level of the cooling water is determined so that the cooling water covers the spent fuel stored in the main body to facilitate the removal of decay heat. Therefore, when cooling water is injected into the main body of a can containing spent fuel, the liquid level is maintained at the predetermined level.

As a method of this kind, the method shown in FIG. 2 is conventionally known. In Fig. 2, 1 is a cylindrical body of a canned food;
The upper end opening 1a of the main body 1 is sealed by a lid (not shown). The spent fuel 2 is stored in the main body 1, and is injected into the main body 1 through the water injection pipe 3 so that the cooling water 7 is filled and held within the main body 1. In this case, as described above, in order to maintain a predetermined liquid level, the amount of water injected is adjusted while visually observing the liquid level 7a of the cooling water reflected on fR4 through the observation window 5.

In such an operation, if too much water is injected, the water removal plug 6 is inserted as shown in FIG. 3, and the water removal plug 6 is removed from the water removal hole 6a provided in the water removal plug 6. Cooling water is discharged to the outside to maintain a predetermined level.

The canning operations described above are carried out in a canning room that is shielded from the radiation emitted by spent fuel. Therefore, the above-mentioned viewing window 5 is provided on the wall of the canning chamber, and water pouring, which is one of the canning operations, is also performed by remote control.

However, in the water injection method as described above, in order to maintain a predetermined level of the cooling water, the liquid level is adjusted visually using a water removal plug, so automation is difficult. Further, the water removal plug cannot be inserted into the main body of the can to discharge an excessive amount of water unless the inner diameter of the main body of the can is equal to or smaller than the inner diameter of the upper end opening.

Recently, in order to facilitate the insertion of spent fuel cans into the main body, the inner diameter of the upper part 1b of the main body 1 of the can can is changed to the upper opening 1a of the main body 1, as shown in FIG.
It is planned that the structure will be larger than the inner diameter of the Therefore, with this structure, even if the water removal plug is inserted into the main body from the upper end opening 1a, the cooling water in the inner diameter part of the upper part of the main body, which is larger than the upper end opening, is not discharged by the water removal plug, making it impossible to maintain a predetermined liquid level. There is a problem.

[Purpose of the invention]

In view of the above-mentioned points, the present invention can accurately maintain the liquid level of the cooling medium filled in the main body containing the reactor fuel, especially the spent fuel, at a predetermined value, and can automate the filling of the cooling medium. The object of the present invention is to provide a cooling medium injection device for fuel canisters.

[Summary of the invention]

According to the present invention, the reactor fuel is stored in the cylindrical body, the cooling medium is filled up to a predetermined liquid level, and the upper end opening is sealed with a lid for injection of cooling medium into the fuel can. In the apparatus, an injection conduit comprising a supply tank that stores the cooling medium, a first valve that is insertable into the main body, and that supplies the cooling medium from the supply tank into the main body, and a flexible pipe. and a discharge tank connected to a conduit having a second valve branching from the inlet conduit from the conduit between the first valve and the flexible tube.

[Embodiments of the invention]

The present invention will be described in detail below based on the drawings.

FIG. 1 is a system diagram of a cooling medium injection device for a fuel canister according to an embodiment of the present invention. In FIG. 1, the same parts as in the conventional example shown in FIGS. 2 and 3 are given the same reference numerals, and their explanations are omitted. In FIG. 1, 1 is the main body of a cylindrical can, and the lid 20 indicated by the dashed line is connected to the top opening 1.
It is inserted into the main body 1 of the canned can from the position a, and is fastened to the main body upper part 1b by the tightening means, so that the main body 1 is sealed. By the way, as mentioned above, the inner diameter of the upper part 1b of the main body is larger than the inner diameter of the upper end opening 1a. The spent fuel 2 is stored at a position below a predetermined liquid level 7a of the cooling water 7 filled in the main body 1.

Reference numeral 9 denotes a supply tank that stores cooling water to be filled into the main body 1, and the supply tank 9 is provided with a level gauge 17 that indicates the liquid level of the stored cooling water. An injection conduit 8 having a pneumatically operated stop valve 13 as a first valve and a flexible tube 8a is provided from the bottom of the supply tank 9, and the distal end of the injection conduit 8 is inserted into the main body 1. possible.

The discharge tank 10 is connected to a discharge line 18 branching from the injection line 8 between the stop valve 13 and the flexible tube 8a, and the discharge line 18 includes a pneumatically operated stop valve 12 as a second valve. It is provided. A vacuum pump 11 as a suction device is also provided, which is connected to the discharge tank 10 by a conduit 19 having a pneumatically operated stop valve 14 . In addition, level meter 1
6 is provided in the discharge tank 10 to detect the level of cooling water accumulated in the discharge tank 10. Also, discharge tank 1
A discharge pipe 21 having a pneumatically operated stop valve 15 for discharging the cooling water accumulated in the discharge tank 10 is provided at the bottom of the discharge tank 10.

Next, a method for injecting cooling water into the main body of a fuel can using such a system configuration will be explained.

First, the stop valves 12 and 15 are closed, the stop valve 14 is opened, and the vacuum pump 11 is driven to maintain the inside of the discharge tank 10 in a vacuum. Next, the stop valve 13 is closed, and the supply tank 9 is filled with an amount of cooling water that is slightly longer than the amount of cooling water required to fill the main body 1 and maintain a predetermined liquid level. Note that the amount of cooling water in the supply tank 9 can be confirmed using a level meter 17.

In this state, the injection pipe 8 is inserted through the upper end opening 1a of the main body 1 of the can by bending the flexible pipe 8a, and the stop valve 13 is opened to drain the entire amount of cooling water in the supply tank 9 into the main body 1. Inject into. At this time, the liquid level of the main body 1 forms a liquid level 7b higher than the predetermined liquid level 7a. Next, the injection pipe 8 is moved by bending the flexible tube 8a, and the tip opening 8b of the injection pipe 8 is aligned with the position of the predetermined liquid level 7a.

Then, when the stop valve 13 is closed and the stop valve 12 is opened, the excess cooling water filled in the main body 1 is sucked up to the tip opening 8b of the injection pipe 8 due to the vacuum of the tank 10, and a predetermined amount is drawn up. The liquid level 7a is maintained, while the spattered cooling water remains in the discharge tank 10.

Note that the level meter 1 determines whether or not the predetermined liquid level 7a is maintained.
By measuring the water level in the discharge tank 10 in step 6, it can be confirmed that the cooling water level in the main body 1 is at a predetermined level. After confirmation, the stop valve 15 is opened to discharge the cooling water accumulated in the discharge tank 10 from the discharge pipe 21, thereby making it possible to pour water into the main body 1 of the next fuel can.

〔Effect of the invention〕

As is clear from the above description, according to the invention, there is provided a supply tank connected to an injection line having a first valve and a flexible tube for injecting a cooling medium into the main body of a fuel canister; By providing a discharge tank that is branched from the pipeline and connected to a discharge pipeline having a second valve and that can maintain negative pressure, the first
Open the valve to inject the amount of cooling water from the supply tank into the main body from the injection pipe, and insert the injection pipe to a predetermined liquid level in the body to suck up the excess cooling water by the negative pressure of the discharge tank. As a result, the liquid level within the main body can be maintained at a predetermined value, and there is no need to visually monitor and adjust the liquid level within the main body, so automation can be easily achieved.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a cooling medium injection device for a canned fuel can according to an embodiment of the present invention, FIG. 2 is a block diagram of a conventional cooling medium injection device for a canned fuel can, and FIG. FIG. 3 is a cross-sectional view of the plug attached to the fuel canister. 1: Main body, 2: Spent fuel as reactor fuel. 7; cooling water as cooling medium, 8: injection pipe, 9; supply tank, 10; discharge tank, 11; vacuum pump as suction device, 12: second valve, 13; first valve, 18;
Exhaust pipe. Figure 1 Figure 1B2 Figure 3

Claims (1)

[Claims] In a cooling medium injection device for a fuel can, in which reactor fuel is stored in a cylindrical body, the cooling medium is filled to a predetermined liquid level, and the upper end opening is sealed with a lid, the supply for storing the cooling medium. an injection conduit including a first valve and a flexible tube that are insertable into the main body and supply cooling medium from the supply tank into the main body; A discharge tank connected to a discharge pipe line having a second valve branching from a pipe line between the valve and the flexible pipe, and a suction device connected to the discharge tank. Coolant injection device for fuel canisters.