JPH095492A - Nuclear power plant cask cleaning facility - Google Patents

Abstract

(57) [Summary] [Purpose] To eliminate cask cleaning pits, improve work efficiency, and reduce exposure. [Structure] A cover 20 provided on the cask pit 2 for preventing splashing of cleaning water, cask detection devices 11a to 11c for detecting the movement position of the cask 7, a cleaning device 10 for discharging cleaning water, and a cleaning device 10. Cleaning device moving rail 10 for moving, drying device 19 for discharging dry air, drying device 19
It is provided with a drying device rotating rail 18 for moving the rotating device, a rotating rail moving device 17, measurement monitors 16a to 16c for measuring the contamination state of the cask and the cleaning effect, and television cameras 12a and 12b. As the cask 7 is lifted, the cask positions are detected by the cask detection devices 11a to 11c, and the cleaning device 13 and the drying device 19 are operated to clean and dry the cask 7. Measurement monitors 16a to 16 during and after cleaning
In c, the contamination state of the cask 7 and the cleaning effect are measured, and the amount of cleaning water, the strength of pressure, and recleaning are performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cask cleaning facility for a nuclear power plant for cleaning a shielded cask for containing and storing highly radioactive substances such as spent fuel.

[0002]

2. Description of the Related Art In a nuclear power plant (controlled area), a cask is used for loading and storing or transporting an object to be transported such as a spent fuel taken out from a core or one having high radioactivity. This cask is generally a container in which lead is filled as a shielding material between an outer cylinder made of steel and an inner cylinder made of stainless steel, and the transported object is accommodated in the inner cylinder.

The place where these transported objects are loaded into the cask is carried out in the cask pit 2 provided at one corner of the fuel pool as shown in FIG. 8 in order to protect workers from radiation exposure. 8 is a layout diagram of the reactor building fuel handling floor 3 showing the positional relationship between the cask pit 2 and the cask cleaning pit 6 of a general plant. In FIG. 8, reference numeral 4 is a reactor well, and 5 is an equipment storage pit. Is shown.

Since the work of loading the object to be transported into the cask is performed underwater, the surface of the cask is polluted by the pool water of the fuel pool 1. For this reason, after taking out the cask from the cask pit 2, it is necessary to clean the surface of the cask to such an extent that it can be carried out of the nuclear power plant (controlled area).

Conventionally, in this cleaning work, as shown in FIG. 9, a cask 7 is installed in a cask cleaning pit 6 and a cleaning device 8 cleans the cask 7. That is, the cask 7 removed from the cask pit 2 shown in FIG.
After draining water above, the cask 7 is transferred to a dedicated cask cleaning pit 6 provided for cleaning, and the outer surface of the cask 7 is cleaned by a cleaning device 8.

Generally, the cask 7 is washed in the cask washing pit 6 from above the cask 7 by manually sprinkling water with a dedicated hose or the like and then wiping it off with a waste cloth. It is being appreciated. Therefore, as shown in FIG. 9, scaffolds 9 are provided in the cask cleaning pit 6 at intervals such as in the height direction so that an operator can easily access the cask 7.

FIG. 9 shows a conventional cask cleaning pit 6, and reference numeral 8 in the drawing denotes a cleaning device. In some plants, the cask is cleaned by an automatic cleaning device that cleans with a high-pressure water jet nozzle or a mechanical brush and dry with a high-pressure air nozzle.

[0008]

Since the conventional cask cleaning facility of the nuclear power plant requires the dedicated cask cleaning pit 6, it occupies the space of the reactor building fuel handling floor 3 and also can be installed in the downstairs equipment. Since the cask 7 is cleaned in the closed space of the cask cleaning pit 6, the cleaning worker is exposed to a large amount of radiation and the working time is long. In addition, when the cask is transferred from the cask pit 2 to the cask cleaning pit 6, the contaminated water falls on the reactor building fuel handling floor 3 and there is a problem that the pollution spreads.

The present invention has been made in order to solve the above-mentioned problems, and improves work efficiency when cleaning a cask, shortens cask handling time, reduces radiation exposure of workers, cask pit and cask cleaning pit. It is an object of the present invention to provide a cask cleaning facility for a nuclear power plant, which can avoid the spread of pollution around it and can remove the cask cleaning pit, and can increase the degree of freedom in the space of the reactor building fuel handling floor and the equipment layout below.

[0010]

According to the present invention, there is provided a lower device rotating rail disposed on a cask pit provided in a fuel handling floor of a reactor building, and a standing member perpendicular to the lower device rotating rail. And a guide rail, an upper device rotation rail horizontally disposed above the support column and the guide rail, and attached to at least one of the upper device rotation rail and the lower device rotation rail. It is characterized by comprising the cask detection device, the cleaning device, the drying device, the television camera and the rotation moving device, and the plurality of measurement monitors provided on the support.

[0011]

The cleaning equipment of the present invention automatically detects the movement and contamination state of the cask, and automatically cleans, dries and inspects the cask. This cleaning equipment is installed on the cask pit where the cask is hoisted, and the hoisting and inspection are automatically performed while hoisting the cask.

That is, as the cask is lifted, the cask position is detected by the cask detection device, and the cleaning device and the drying device are operated to clean the cask. During the cask cleaning, the cover prevents the spray water from spreading.

During and after cleaning, the contamination state of the cask and the cleaning effect are measured with a measurement monitor, and the amount of cleaning water and pressure are adjusted, and re-cleaning is performed. Rails for rotating each device rotate and move the cleaning device, drying device, cask detection device, and TV camera. The cleaning device discharges cleaning water, and the drying device discharges dry air.

[0014]

EXAMPLE An example of cask cleaning equipment for a nuclear power plant according to the present invention will be described with reference to FIGS. 1 to 7.
FIG. 1 shows the overall configuration of the cask cleaning equipment according to the present embodiment, FIG. 2 is a plan view in the direction of arrows AA in FIG. 1, FIG. 1 is an elevation view showing a state in which the cover is set in the cask pit and extended, FIG. 5 is an external view showing an installation state of the cleaning device in FIG. 1, and FIG. 6 is an external view showing an installation state of the drying device in FIG. 7 and 8 are external views showing a moving state of the cask in FIG. 1 during cleaning.

In FIG. 1, a cleaning device rotating rail 10 as a lower device rotating rail is provided on the cask pit 2. Caskpit 2 is floor 3 of the reactor building
It is provided in. The cleaning device rotating rail 10 has a first cask detecting device 11a, a second cask detecting device 11b,
A first TV camera 12a and a cleaning device 13 are attached.

A column 14 and a guide rail 15 are provided upright in a direction perpendicular to the rail 10 for rotating the cleaning device. Post 14
A first measurement monitor 16a, a second measurement monitor 16b, and a third measurement monitor 16c are attached to the. A rotation rail moving device 17 is attached to the guide rail 15.

A drying device rotating rail 18 as an upper device rotating rail is attached to the rotating rail moving device 17. A dryer 19, a third cask detector 11c and a second television camera 12b are attached to the dryer rotation rail 18. A cover 20a is provided so as to surround the rail 10 for rotating the cleaning device, the rail 18 for rotating the drying device, the support 14 and the guide rail 15 as a whole.

As shown in FIG. 4, the cover 20 is mainly formed of a bellows-shaped elastic member 20a, and when the ring-shaped member 20b provided at the upper end of the elastic member 20a is lifted up, it becomes a cylindrical shape. The elastic member 20a is formed of rubber, synthetic resin or thin metal in a bellows shape.

The cleaning device 13 has a cleaning device driving section 21 and a cleaning device rotating section 22 as shown in FIG. 5, and the drying device 19 has a drying device driving section 23 and a drying device as shown in FIG. Rotating part
Has 24. The cover 20 is stretchable because it can prevent the diffusion of washing water during cleaning and can change the shape of the elastic member 20a.

The first to third cask detection devices 11a to 11
The c is attached to a key portion in the height direction to detect the movement of the cask. The cleaning device 13 releases cleaning water for cleaning the cask 7. The cleaning device driving unit 21 is a cleaning device 13
Drive up and down. The cleaning device rotating unit 22 is a cleaning device.
Rotate 13.

The cleaning device rotating rail 10 serves as a guide when the cleaning device 13 is rotated. The drying device 19 is for cleaning and drying the cask 7. The dryer driving unit 23 drives the dryer 19 up and down. The dryer rotating unit 24 rotates the dryer 19.

The drying device rotating rail 18 serves as a guide when the drying device 19 is rotated. The rotating rail moving device 17 moves the drying device 19 up and down together with the drying device rotating rail 18. The guide rail 15 holds a rail 18 for rotating the dryer.

The first to third measurement monitors 16a to 16c check the contamination state of the surface of the cask 7 and confirm the cleaning effect. The first and second television cameras 12a and 12b visually confirm the surface of the cask 7. The columns 14 support devices such as a cask cleaning facility including the cover 20.

The operation of the embodiment of the present invention will be described below. The columns 14, the guide rails 15 and the cover 20 are set on the cask pit 2 in advance. At this time, as shown in FIG. 4, the elastic member 20a of the cover 20 is folded and tightened. Further, the drying device 12 is set in a state of being raised to the top.

After loading an empty cask 7 into the cask pit 2 and loading the object to be transported into the cask 7, the cask 7 is lifted by an overhead crane. Before hoisting the cask 7, the cover 20 is pulled upward to spread it to prevent splashing of washing water. Start lifting the cask 7,
When the cask 7 is lifted above the water surface and passes the first cask detection device 11a, the cleaning device 13 starts discharging cleaning water obliquely downward.

Further, as is apparent from FIG. 3, the cleaning devices 13 are provided at four positions on the plane at equal intervals, and are repeatedly moved by 90 ° by the cleaning device rotating portion 22 to cover the entire circumference of the cask 7. While releasing the wash water. Cleaning device rotating part 22
Is driven by a small electric motor. Cask 7 as it is
And the first cask detection device 11a lifts the cask 7
While detecting, the cleaning device 13 continues to discharge water and cleans the cask 7 from the upper surface to the side surface.

Further, when the cask 7 is lifted up and passed through the second cask detection device 11b, the cleaning device 13 changes the discharge angle of the cleaning water obliquely upward so that the lower surface of the cask 7 can be cleaned. The angle of the cleaning device 13 is driven by a small electric motor. The cask 7 is continuously lifted, and when the third cask detection device 11c detects the cask 5, the cleaning device 13 stops water discharge.

On the other hand, the drying device 19 starts to operate when the second cask detecting device 11b detects the cask 7, and discharges dry air obliquely downward to the cask 7. The drying device 19 descends along the guide rail 15 by the rotating rail moving device 17.

The rotating rail moving device 17 is composed of a small electric motor, a speed reducer and a gear, and moves along a guide rail 15 having a groove for receiving the gear. Further, as is apparent from FIG. 2, four drying devices 19 are provided at equal intervals on a plane, and in order to cover the entire circumference of the cask 7, the drying device rotating portion 24 repeatedly performs dry air movement for 90 degrees. To release.

The dryer rotating unit 24 is driven by a small electric motor. When the third cask detecting device 11c detects the cask 7, the drying device 19 turns obliquely upward to dry the lower end portion of the cask 7. After that, the drying device 19 is stopped by the timer after the third cask detection device 11c detects the cask 7 and a certain time has elapsed.

The first to third measurement monitors 16a to 16c are attached to the support column 14 and constantly measure the contamination state of the surface of the cask 7 during and after cleaning. Measurement monitor 16a-
16c always measures the state of contamination on the surface of the cask 7,
Automatically adjust the wash water volume and wash pressure. Further, if the result of the third measurement monitor 16c after cleaning indicates that re-cleaning is necessary, the cask 7 is suspended again and the cleaning work is performed.

Further, during cleaning, since the cleaning condition cannot be visually confirmed by the cover 20, the first to second television cameras
Check the cask cleaning status with 12, 12b. The TV cameras 12a and 12b are incorporated in the cask cleaning device at four positions, respectively at the upper part and the lower part. This TV camera 12a,
12b is also used to confirm the outer surface of the cask 7 after cleaning.

[0033]

[Table 1]

Table 1 shows the operating states of the respective devices, and FIG. 7 shows the positions of the first to third cask detecting devices when the cask 7 moves upward corresponding to the table 1. I to IV in FIG. 7 correspond to states I to IV in Table 1.

According to this embodiment, since the cask 7 is washed while being lifted from the cask pit 2, the efficiency of the cask cleaning work can be improved, and the cask 7 is also inspected during a series of cask cleaning operations. Therefore, the handling work time of the cask 7 can be significantly reduced. In addition,
By shortening the work time for handling the cask 7 and performing remote work, the exposure of workers can be reduced.

Further, since the cleaning work can be performed in the cask pit 2, the conventional cask cleaning pit 6 can be deleted, and the cask pit 2 and the cask cleaning pit 6 can be eliminated.
It is possible to avoid the spread of pollution around and increase the flexibility of the reactor building fuel handling floor space and the equipment layout below.

In the above embodiment, after closing the gate attached to the cask pit 2, draining water from the cask pit 2 and installing the above-mentioned cask cleaning equipment in the cask pit 2 Cleaning can also be performed.

[0038]

According to the present invention, the conventional cask cleaning pit is deleted, the cask is cleaned automatically on the cask pit or in the cask pit while preventing the spread of contamination, and the outer surface of the cask is also inspected. It can be carried out.

Therefore, the work efficiency at the time of cleaning the cask is improved, the time for handling the cask is shortened, the exposure of workers is reduced, the spread of contamination around the cask pit and the cask cleaning pit is avoided, and the space for the fuel handling floor of the reactor building and The degree of freedom in arranging the equipment downstairs can be increased.

[Brief description of drawings]

FIG. 1 is an elevation view showing an embodiment of a cask cleaning facility for a nuclear power plant according to the present invention, with a part thereof cut open.

FIG. 2 is a plan view seen from the direction of arrow AA in FIG.

FIG. 3 is a plan view seen from the direction of arrows BB in FIG.

FIG. 4 is an elevation view for explaining a state in which the cover in FIG. 1 is set in the cask pit and extended.

FIG. 5 is an external view showing an installed state of the cleaning device in FIG.

FIG. 6 is an external view showing the installation state of the drying device in FIG.

FIG. 7 is a conceptual diagram for explaining a moving state of the cask in FIG. 1 during cleaning.

FIG. 8 is a layout diagram showing a reactor building fuel handling floor for explaining a conventional cask cleaning facility.

FIG. 9 is a schematic view showing the cask cleaning pit of FIG.

[Explanation of symbols]

1 ... Fuel pool, 2 ... Cask pit, 3 ... Reactor building fuel handling floor, 4 ... Reactor well, 5 ... Equipment storage pit,
6 ... Cask cleaning pit, 7 ... Cask, 8 ... Cleaning device, 9 ... Scaffolding, 10 ... Rail for rotating cleaning device, 11a ... First
Cask detection device, 11b ... second cask detection device,
11c ... third cask detection device, 12a ... first television camera, 12b ... second television camera, 13 ... cleaning device, 14 ...
Column, 15 ... Guide rail, 16a ... First measurement monitor, 16
b ... 2nd measurement monitor, 16c ... 3rd measurement monitor, 17 ...
Rotating rail moving device, 18 ... Drying device rotating rail, 19
... Drying device, 20 ... Cover, 20a ... Stretchable member, 20b ... Ring-shaped member, 21 ... Cleaning device drive part, 22 ... Cleaning device rotating part,
23 ... Drying device drive part, 24 ... Drying device rotating part.

Claims (5)

[Claims] 1. A rail for rotating a lower device arranged on a cask pit of a fuel handling floor of a reactor building, a column and a guide rail standing upright in a direction perpendicular to the rail for rotating the lower device, and the column and the guide. An upper device rotation rail which is located above the rail and which is horizontally arranged, and a cask detection device, a cleaning device, and a drying device which are attached to at least one of the upper device rotation rail and the lower device rotation rail. , A cask cleaning facility for a nuclear power plant, comprising a television camera, a rotary moving device, and a plurality of measurement monitors provided on the support. 2. A cover installed on the cask pit and surrounding the cask to be cleaned and the upper device rotating rail to the lower device rotating rail, the support column and the guide rail. 1. Cask cleaning equipment of the nuclear power plant described in 1. 3. A first cask detecting device and a second cask detecting device, a first television camera and a cleaning device are attached to the lower device rotating rail, and a third cask detecting device is attached to the upper device rotating rail. The cask cleaning facility for a nuclear power plant according to claim 1, wherein the device, the second television camera, and the drying device are attached. 4. The cask detection device, a television camera,
2. The cask cleaning facility for a nuclear power plant according to claim 1, wherein a plurality of cleaning devices and drying devices are radially arranged on at least one of the upper device rotating rail and the lower device rotating rail. 5. The cask cleaning equipment for a nuclear power plant according to claim 2, wherein the cover has a ring-shaped member at an upper end thereof, and a bellows-shaped elastic member on a lower surface of the ring-shaped member.