JPS59157596A - Method and device for removing crud of reactor fuel pool - 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 The present invention relates to a method and apparatus for removing crud as radioactive contaminants deposited in a fuel pool for storing spent fuel provided in a nuclear facility.

When the door between the reactor side and the pool is opened to move the spent fuel from the reactor to the fuel pool, radioactive contaminants from inside the reactor flow into the pool and accumulate on the fuel rack, pool, and bottom. Moreover, these deposits are highly radioactive, making it difficult to treat them using the conventional treatment method of placing a filter container in a drum with a lead shield inside.

drums are required. Not only the amount of drums used, but also the amount of radiation exposure for workers, so a more economical and safer work method is needed. Also, is there a differential pressure gauge that can be used to determine the amount of crud collected in conventional filter devices installed underwater? Since it is installed at +1X, the pointer of the differential pressure gauge of the filter device located at the bottom of water over 10m is difficult to see from the water surface due to the movement of the water in the pool, and the fitting operation is a rotary lock method. ,
When detached, the filter device itself rotates together with the attachment/detachment device, making detachment difficult.Also, there was a drawback that workers were exposed to radiation during detachment work.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome these drawbacks of the prior art and to provide a crud removal method and apparatus that can effectively and safely collect crud.

To summarize the configuration for achieving the above ten purposes, the components of the water circulation system including the cladding include a nozzle, a solid separation device, a pump, a filter device N, a hose connecting these, and a hose and a filter. By placing all of the equipment's attachment/detachment devices underwater, it is possible to prevent workers from being exposed to radiation. In addition, the valves for operating the opening/closing lid of the solids separator, the attachment/detachment device for the hose and filter device, the pressurization device for operating air, the pump switch, the pressure gauge for the filter, and the alarm device to notify the usage limit of the filter are installed on the floor. It is characterized by being installed on the operation panel.

A preferred embodiment of such a configuration will be described below. Figure 1 shows the water circulation system of the device submerged in a fuel pool. Water containing crud is sucked through the nozzle 1 and enters the solids separator 6 through the hose 2. The solid matter separator 6 consists of a strainer 4, an air-operated opening/closing lid 6 for dropping accumulated solid matter into a container 5, and a submersible pump 7 for backwashing to remove solid matter adsorbed by the strainer 4. ing. The water that has passed through the solid matter separator 5 passes through a submersible pump 8 and is guided by a drain hose 9 to a filter device 10 containing a number of filters, where the filtered clean water is discharged into the fuel pool 11 again. .

Figure 2 is an enlarged view of the solid matter separator B. When the submersible pump 8 is operated, the crud and water sucked in from the hose 2 pass through the strainer 4 and go to the submersible pump 8. There are deposits, and these deposits are sucked together with water from the nozzle, and the light and soft ones gradually adhere to the surface of the strainer 4, gradually increasing the flow resistance. A pressure transmission tube 13 is connected to a vacuum gauge 14 attached to an operation panel (not shown) on the floor from a pipe 12 that connects the submersible pump 8 and backwash pump 7 to the strainer 4 via valves (not shown), respectively. It is connected to the. Therefore, as described above, if a large amount of pool bottom sediment adheres to the surface of the strainer 4 and the water flow is not obstructed, the attached dust can be easily detected by the amplitude of the vacuum gauge 14.

When the pointer of the vacuum gauge 14 begins to swing in this manner, the deposits are removed in the following manner. That is, first, the operation of the submersible pump 8 is stopped. Next, the air cylinder 16, which is rotatably supported at one end on both sides of the strainer box 15 and rotatably supported at the other end by the opening/closing lid 6 hinged to the lower end of the strainer box 15, is actuated. is opened downward (as shown by the two-dot chain line in Fig. 2) and the backwash pump 7 is started to remove the deposits adhering to the surface of the strainer 4 by passing water from the opposite direction, that is, downward from the child side. The solids are housed in a solid container 5 installed under the strainer box 15 and having an opening at the top.

When the adsorbed matter has been removed, the operation of the backwash pump 7 is stopped, and
Operate the air cylinder I6 to close the opening/closing lid 6 (solid line position in Figure 2). This work makes it possible to efficiently absorb tree cladding again.

FIG. 3 shows a device for attaching and detaching the discharge port 9 and the filter device 10. A short pipe 17 connecting the discharge side hose 9 and the socket 19 has a G lever 18 welded to it so that an operating rod (not shown) can be detached from it. Sleeve 2 of socket 19
0 by driving the air cylinder 2] and pulling up the internal locking device (details are omitted,
6 to 125164), and then insert the socket 19 into the plug 22, which is the water inlet of the filter device 10, using the operating rod attached to the claw 18. Then air cylinder 2
When the first operation valve is shifted to the neutral position, the sleeve 20 is automatically lowered by the force of the spring contained in the locking device, and the socket 19 is fitted with the plug 22. At the same time that the socket 19 and the plug 22 are fitted together, the socket 19 and the plug 2
The valve in 2 opens and the crud and water from the hose 9 flow into the filter device 10.

On the other hand, when detaching the attachment/detachment device from the filter device 10, it is easy to remove the sleeve 20 by pulling up the sleeve 20 with the air cylinder 21 to release the locking device, and then pulling the discharge port 9. When the socket 19 and plug 22 are separated,
The valves built into each valve close the flow paths to each other under the force of a spring. The above-mentioned fitting and detaching operations can be easily performed by remote control of an air cylinder, and in the case of fitting, the socket can be simply pushed in using an operating rod.

9- Also, a pressure transmission tube 23 is connected from the short pipe 17 to a pressure gauge 24 and a pressure switch 25 attached to an operation panel on the floor, so that the water pressure in the filter device 10 reaches the working limit pressure of a filter (not shown). When the pressure is reached, a signal device G such as a buzzer connected to the pressure switch 25 issues a signal. Therefore, even when using a filter that tends to cause a sudden pressure increase near its usage limit, the operator does not need to constantly pay attention to pressure fluctuations in the filter.

FIG. 4 is a system diagram of the air that operates the solid matter separation device 6 and the hose and filter device attachment/detachment device. Air source 2
The pressure air coming from 6 is adjusted to the required pressure by the pressure reducing valve 27 plus a back pressure which will be described later, and then the pressure air is adjusted to the required pressure by the pressure reducing valve 27.
. Therefore, water will not enter the air system. Also, when switching the valve, the high pressure air from the 1 operation side comes out to the discharge side, but this is discharged by the IJ IJ-7 valve built into the pressure reducing valve 29, making it easy to operate the cylinder. be able to.

The filter device 10 has several dozen cartridge filters inside, and the inflow of cladding and water into the device is through a plug 22 that has an internal valve and opens the valve only when connected to a socket, so the filter device itself Even when moving, the internal cladding will not leak out. However, since only fresh water filtered by the filter passes through the water outlet of the filter device, an open pipe is installed.

Therefore, according to this crud removal method, even if the pipe line is blocked due to the inflow of solid matter deposited at the bottom of the fuel pool, crud can be accommodated up to the usage limit of the filter while eliminating it, and it is also possible to accommodate the crud up to the usage limit of the filter. Even if the work is stopped before the crud has been accommodated to the limit, the above-mentioned hose and filter device attachment/detachment device allows the work to be completed with only the filter device left at the bottom of the fuel pool, so that it can be used for the next time. By connecting the discharge side hose again to the filter device, it is possible to accommodate the crud up to the usage limit of the filter.

[Brief explanation of drawings]

FIG. 1 shows a crud removal device according to the present invention submerged in a fuel pool. Figure 2 is an enlarged detailed view of the solids separation device. FIG. 3 shows a device for attaching and detaching the discharge side hose and the filter device, and FIG. 4 shows an air system diagram for operating the device for attaching and detaching the solid matter separator and the hose and the filter device. In the figure: 1 Nozzle 2 Hose 3 Solid matter separator 4 Strainer 5 (Solid matter storage) container 6 Opening/closing lid 7 (For backwashing) Submersible pump 8 Submersible pump 9 Discharge side hose 10
Filter device 11 Fuel pool 12 Pipe 13 Pressure transmission tube 14 Vacuum gauge 15
Strainer box 16 Air cylinder 17 Short pipe
] 8 claws 19 Socket ・20 Sleeve = 13- 21 Air cylinder 22 Plug 23
Pressure transmission tube 24 Pressure gauge 25 Pressure switch 26 Air source 27 Pressure reducing valve
28a, 28b Switching valve 29 Pressure reducing valve and above Applicant: Nuclear Power Agency Co., Ltd. Patent Attorney Isamu Ohashi 14- Fig. 1 Gokoku 4 1st Unexamined Patent Publication No. 1983-157596 (5) Fig. 3 Fig. 4 Electric sound・

Claims (1)

[Claims] 1) A pump that sucks crud together with water in a method for removing crud as radioactive contaminants deposited in a fuel pool for storing spent fuel installed in a nuclear reactor facility, and a pump that sucks crud together with water; and filter devices that separate and collect crud from water, solid separation devices related to filter devices,
A hose and an attachment/detachment device for the hose and filter device were installed underwater, and an operation panel loaded with operation valves, instruments, a pressurization device for the operation air exhaust system, and a filter pressure alarm device was installed on the floor. A method for removing crud from a nuclear reactor fuel pool, characterized by: 2) a cladding suction nozzle, a solids separator connected to the suction nozzle with a hose, and a submersible pump connected above the solids separator including a backwashing submersible pump and a solids storage container; It consists of a submersible pump, a filter device that is removably connected underwater via piping, and operating devices for each of these devices, and the operating devices for each device can be controlled remotely from a control panel installed on the floor. A reactor fuel pool crud removal device featuring: