KR102172257B1 - Spent nuclear fuel inspection surface robot and method - Google Patents

Abstract

The present invention relates to a device and a method capable of testing spent nuclear fuel. The apparatus for inspecting spent nuclear fuel according to the present invention comprises: a water moving body having a camera; And a control unit for controlling the moving object, wherein the control unit includes: an image processing unit configured to determine a location of nuclear fuel based on the image captured by the camera; A position control unit controlling a position of the moving object based on the position of the nuclear fuel; A navigation unit that controls the movement of the moving object; And a data management unit that manages the acquired data while the moving object moves.

Description

Spent nuclear fuel inspection surface robot and method

The present invention relates to a device and a method capable of testing spent nuclear fuel. More specifically, it relates to a floating robot and an inspection method for inspecting spent nuclear fuel.

Spent nuclear fuel means nuclear fuel material used as fuel in a nuclear reactor. Spent nuclear fuel emits radiation and high heat, so it is stored and managed in a spent nuclear fuel storage tank, a related facility within a nuclear power plant.

There are hundreds of spent fuel storage tanks around the world, and the approximate size is over 10m x 10m x 10m. Hundreds of spent nuclear fuels are stored in one storage tank, and the number of them is gradually increasing as the nuclear power plant operates.

Accordingly, spent nuclear fuel should be regularly inspected and inspected for reasons of nuclear material proliferation and safety. Currently, the inspection of spent nuclear fuel is a method in which an inspector carries an Improved Cerenkov Viewing Device (ICVD), a special camera device capable of measuring Cherenkov radiation.

Accordingly, problems that may arise from the current spent nuclear fuel inspection method are as follows.

First, in this current inspection method, there is a risk of exposure to radioactivity because the inspector directly performs inspection on the spent fuel storage tank. In addition, since the inspection work is performed on the water surface of the storage tank, there is a risk of an accident in which foreign substances including inspection equipment are dropped into the storage tank.

Each spent fuel should be inspected at the correct location, and each spent fuel inspected should be able to determine its exact location. However, if the watchdog is carrying it, the accuracy is degraded.

In addition, it takes a lot of time to sequentially inspect hundreds of spent nuclear fuels inside the storage tank (size: width x length: 20 x 20 cm or less when viewed from the surface).

Another problem is that inspection methods, plans, and data management are not systematically operated by the automated system.

In addition, existing floating robots are difficult to operate within the radiation area, and there is a problem that software development for mounting and operating inspection equipment is insufficient.

It is an object of the present invention to solve the above and other problems. Another object is to provide an apparatus and method for inspecting spent nuclear fuel that can automatically inspect the health of spent nuclear fuel stored in a spent nuclear fuel storage tank as an unmanned water robot.

According to an aspect of the present invention in order to achieve the above or other objects, a water moving body having a camera; And a control unit for controlling the moving object, wherein the control unit includes: an image processing unit configured to determine a location of nuclear fuel based on the image captured by the camera; A position control unit controlling a position of the moving object based on the position of the nuclear fuel; A navigation unit that controls the movement of the moving object; And a data management unit that manages the acquired data while the moving object moves. It provides a spent fuel test apparatus comprising: a. Here, the spent nuclear fuel inspection device may be a floating robot for inspection of spent nuclear fuel.

In addition, according to another aspect of the present invention, as the water moving object having a camera moves, determining the position of the nuclear fuel based on the image captured by the camera; Controlling the position and movement of the moving object based on the position of the nuclear fuel; And managing the data acquired while the moving object moves. It provides a method for inspecting spent nuclear fuel comprising:

The effects of the apparatus and method for inspecting spent nuclear fuel according to the present invention will be described as follows.

According to at least one of the embodiments of the present invention, by replacing the manual inspection operation method with a robot automation system, it is possible to reduce the radiation exposure of the spent fuel inspector.

In addition, according to at least one of the embodiments of the present invention, it is possible to perform a precise inspection work, there is an advantage that the total inspection period and cost of the spent nuclear fuel can be reduced.

In addition, inspection planning and data management can be systematically operated, and accidents of dropping ICVD equipment into the nuclear fuel storage tank can be prevented.

As another example, in addition to inspection work, it can be used for monitoring the internal condition of the storage tank, and has the advantage of being able to move equipment easily because it is manufactured in a small and light size.

Further scope of applicability of the present invention will become apparent from the detailed description below. However, since various changes and modifications within the spirit and scope of the present invention can be clearly understood by those skilled in the art, specific embodiments such as the detailed description and preferred embodiments of the present invention should be understood as being given by way of example only.

1 is a conceptual diagram illustrating an embodiment of a mobile robot provided in a spent nuclear fuel inspection apparatus according to the present invention.
2 is a conceptual diagram illustrating an embodiment of a robot, a cable, and a control computer.
3 is a conceptual diagram illustrating an embodiment in which the robot is operated.
4 is a conceptual diagram illustrating an embodiment of a control program.
5 is a flowchart of a method for inspecting spent nuclear fuel according to another aspect of the present invention.

1 is a conceptual diagram illustrating an embodiment of a mobile robot provided in a spent nuclear fuel inspection apparatus according to the present invention.

Referring to FIG. 1, the apparatus for inspecting spent nuclear fuel according to the present invention may include a floating body (robot) equipped with a camera. In this regard, the robot may be equipped with equipment capable of measuring Cherenkov radiation.

In addition, the robot can float without sinking in the storage tank because the buoyancy material is located at the top. As an embodiment, a total of four buoyancy materials may be located at the top of the robot. In addition, in the robot, heavy objects such as batteries and propellers 210 are located at the bottom, and light objects such as buoyancy materials are located at the top, thereby creating a restoration moment. It can be made in a structure that does not overturn by generating. In this regard, the propeller 210 is only capable of three degrees of freedom of plane motion, and there is no propeller for diving or floating. Therefore, even if the propeller 210 malfunctions, the robot cannot enter the water.

As another embodiment, the outer shape (body) of the robot may be made of a light plastic type, and the camera 110 and the controller 120 may be positioned in the upper cylinder 100 disposed at the top of the robot. For example, the controller 120 is connected to a control program of the control computer (hereinafter, a controller to be described) to receive a signal from the control program. On the other hand, the controller 120 may control the operation of parts provided in the robot, specifically, the camera 110 and the propeller 210 according to the received signal.

Since the camera 110 is coupled with a tilting motor, it can change its direction upward, front, or downward. On the other hand, the body of the robot may be formed in a structure that can withstand the explosion of the battery. Therefore, even if the battery explodes during operation, it is possible to protect the robot and nuclear fuel.

On the other hand, the distance between the nuclear fuel in the spent fuel storage tank (to be inspected) and the water surface of the storage tank (position of the robot) differs for each power plant. Therefore, the camera can utilize an auto focusing function that automatically focuses according to a distance.

In another embodiment, a battery may be located in the lower cylinder 200 disposed at the lower end of the moving body.

In addition, a mount 310 which is connected to the body of the robot to mount the ICVD equipment 300 and a cylinder in which the ICVD equipment 300 is disposed may be vertically connected to the front of the robot. On the other hand, the water robot system according to the present invention is designed to prevent sinking in water. In this regard, if the system sinks in water, it may damage nuclear fuel due to malfunction or the like. Therefore, the system must be able to float on water with positive buoyancy. At this time, even if the cylinder is damaged and submerged, the floating robot system may be floating on the water by the buoyancy material. In this case, the camera 110 and the controller 120 may be located in the upper cylinder 100, and the upper cylinder 100 may be temporarily submerged according to an external shock or the flow of water. However, the water moving body can be configured to float on the water by a buoyancy material. Therefore, the camera 110 is configured to be able to photograph underwater, and the controller 120 must be waterproofed to be operable underwater.

The bottom of the cylinder on which the ICVD equipment 300 is disposed is made of a transparent material, so that the ICVD inspection equipment can inspect the nuclear fuel under the water surface.

In addition, the main parts of the robot (controller, camera, etc.) are radiation shielding structures.

Since all parts are waterproof, radioactive contaminated water can be prevented from seeping inside the robot, and contaminants can be removed with clear water after work. In this way, the robot body and the main parts of the robot are constructed in a waterproof structure, so it is easy to remove contaminated water after use.

On the other hand, it is possible to prevent loosening of the screws by applying loosening prevention to each screw fastened between main parts. In this way, by preventing the screw from loosening, it is possible to prevent the screw from falling into the storage tank.

As another embodiment, a total of four propellers 210 enable control of front and rear, left and right, rotation in place, and the like.

2 is a conceptual diagram illustrating an embodiment of a robot, a cable, and a control computer.

3 is a conceptual diagram illustrating an embodiment in which the robot is operated.

2 and 3, the robot may be connected to a control computer (control unit) and a wired cable 130, and the spent fuel can be inspected while floating in the storage.

As an embodiment, the robot is connected to a control device (control unit) by a cable, and can perform wired communication.

At this time, the cable 130 is a neutral buoyant material and does not sink or float in water and thus does not interfere with the movement of the robot. In addition, the cable may be made of a soft soft material.

In addition, the cable 130 can tow the robot when the robot malfunctions or power is not supplied. In this regard, the cable 130 is configured so that it does not sink or float in water due to neutral buoyancy and thus does not interfere with the movement of the robot. Specifically, the cable 130 is configured not to interfere with the movement of the moving object by neutral buoyancy. That is, the cable 130 is configured to connect the moving object and the control computer 400 to a length longer than that required for the maximum movement of the moving object. In addition, the cable is made to be sturdy, so that when the robot malfunctions, the robot can be forcibly lifted out of the water. According to an embodiment of the present invention, the cable 130 may connect the controller 120 of the moving object and the controller of the control computer 400. Here, the control unit may refer to the control computer 400 itself, or may refer to a control program executed in the control computer 400 and a device that executes the control program. Accordingly, the controller 120 of the moving object receives a control command from the controller to control the operation of the camera or propeller.

4 is a conceptual diagram illustrating an embodiment of a control program.

Referring to FIG. 4, the control program (control unit or image processing unit) may be composed of a total of four sub programs (sub control unit or sub image processing unit).

First, the image processing program (image processing unit) recognizes the environment inside the storage tank and can classify structures such as the bottom of the storage tank, the wall of the storage tank, the spent fuel, pipes, and pumps.

In particular, even if conditions such as depth or illuminance of the storage tank change, the recognition rate can be maintained by adapting. In this regard, the control program can be configured to adjust the focal length of the camera by sensing different depths of water for each power plant.

On the other hand, since the robot floats on the surface and performs work, precise position control is essential. Accordingly, the position control program (position control unit) estimates the relative position of the robot based on the nuclear fuel classified by the image processing program. In this regard, the control program may be configured to measure the distances between the pipes, pumps, outer walls, etc. in the nuclear fuel storage tank to prevent the robot from colliding. For example, the control program can create a virtual wall to prevent collisions and maintain a safe distance between them.

And, for accurate operation of the inspection equipment, it is possible to perform precise position control.

As an embodiment, the position of the robot may be slightly shifted due to disturbances such as convective water or waves generated from a pump. To compensate for this, the position control program (position control unit) can utilize a posture sensor, an acceleration sensor, and an image processing program. In this case, the attitude sensor and the acceleration sensor may be located in the upper cylinder 100 of the moving body.

Specifically, the position control is a total of two subsystems, it is possible to perform rotation change control and displacement change control.

The rotation change control detects that the robot is twisted in the yaw direction (when the robot is viewed from above, the robot rotates clockwise or counterclockwise based on the center of gravity) and maintains the current state.

The attitude sensor and image processing program can be used for rotational change control.

Specifically, the attitude sensor measures the angle at which the robot rotates. The image processing program can detect in which direction the array of nuclear fuel rotates based on the information coming into the camera.

Accordingly, the rotation angle measured by the attitude sensor and the rotation level of the nuclear fuel array measured by the image processing program are fused to measure the actual rotation change of the robot, and finally, the propeller 210 of the robot is connected to the rotation direction of the robot. By doing the opposite, you can maintain the current posture.

The displacement change control can use the acceleration sensor and the image processing program at the same time.

Specifically, the acceleration sensor measures the acceleration value when the robot moves in the longitudinal direction or the transverse direction, and then calculates the integral to estimate the amount of movement of the robot in the translation direction.

The image processing program can estimate the movement amount of the robot by obtaining a vector in which the nuclear fuel in the image is displaced vertically and horizontally on the screen based on the nuclear fuel at the center.

In this way, the displacement change is estimated by using information from the acceleration sensor and the displacement image processing program, and when displacement occurs, the robot's current position can be maintained by operating the propeller of the robot in the opposite direction.

The position control program can also rotate the robot by measuring the relative angular error value when the current position of the robot is not parallel to the nuclear fuel arrangement direction, thereby aligning the robot's posture to be parallel to the nuclear fuel arrangement.

The navigation program (navigation unit) allows the robot to move within the reservoir in manual or automatic mode. In this regard, the control program may be configured to be able to create a map by grasping different structures for each power plant.

Manual mode can be used when the inspector initially floats the robot on the water, then moves the robot with nuclear fuel to be inspected, or when the robot is retrieved.

The automatic mode is used by the robot to determine its own location in the nuclear fuel storage tank and to plan the inspection route. In the automatic mode, it manages the location of the nuclear fuel currently being inspected and the data from the existing inspection equipment, and shows it to the inspector.

Meanwhile, in the case of conventional nuclear fuel inspections, inspectors used inspection equipment to report each nuclear fuel and record its soundness by hand. In other words, inspection records were not systematically digitized or managed.

The data management program (data management unit) may store video information of inspection equipment, camera information of an underwater robot, movement information of the robot, operation time, and the like.

Since the inspection equipment video information and the underwater robot camera information have different viewing angles, positions, fields of view and recording time, they can be unified and stored.

In addition, the location, date, and time of each fuel storage tank can be recorded, and the location of each nuclear fuel and video information of the inspection equipment can be matched and stored.

In addition, it is possible to compare values taken at different time zones in the same place with each other, and perform a function of classifying according to the use time and place of the equipment.

On the other hand, since inspection work takes a long time, it is necessary to prevent overload and malfunction of the system. In this regard, a wireless power-off switch for remotely stopping the robot in case of malfunction may be provided.

Accordingly, as a system protection program (system protection unit), the battery management program may measure the amount of power used and voltage of the battery to inform the remaining amount of the battery and the replacement time.

On the other hand, in the case of a wired system, when the underwater robot rotates in one direction, the string is constantly twisted. In order to compensate for this, the cable protection program measures the amount of rotation of the robot and, when excessively rotated in one direction, rotates in the opposite direction to prevent twisting of the string.

And, if the robot is used in a nuclear fuel storage tank, it is continuously exposed to radiation. Therefore, in order to prevent the robot from malfunctioning or malfunctioning, it is necessary to estimate the exposure amount of the main parts and replace the parts at an appropriate time.

The system protection program (system protection unit) estimates the exposure amount of major electronic components in consideration of the movement path and operating time of the robot, and can inform the replacement of major components when the standard exposure limit is reached.

In the above, a spent nuclear fuel inspection equipment according to the present invention, that is, a water robot for inspection of spent nuclear fuel, has been described. Hereinafter, a method for inspecting spent nuclear fuel according to another aspect of the present invention using such inspection equipment, that is, a floating robot will be described.

In this regard, FIG. 5 shows a flowchart of a method for inspecting spent nuclear fuel according to another aspect of the present invention. Referring to FIG. 5, the method for inspecting spent nuclear fuel includes determining the position of nuclear fuel (S100), controlling the position and movement of the moving object (S200), and managing the acquired data (S300). Meanwhile, the above-described steps may be performed by the above-described control program (control unit or processing unit).

In the step (S100) of determining the location of the nuclear fuel, as the aeroplane moving object equipped with the camera moves, the location of the nuclear fuel may be determined based on the image captured by the camera.

In addition, in the step of controlling the position and movement of the moving object (S200), the position and movement of the moving object may be controlled based on the position of the nuclear fuel.

In this regard, in the step of controlling the position and movement of the moving object (S200), the rotation angle of the moving object may be measured using a posture sensor. In addition, by detecting the direction in which the array of nuclear fuel rotates in the image captured by the camera, the position of the moving object may be controlled so that the posture of the moving object can be maintained.

Meanwhile, in the step of controlling the position and movement of the moving object (S200), the degree to which the moving object has moved in a predetermined direction may be calculated using an acceleration sensor. In addition, it is possible to control the position of the moving object so that the posture of the moving object can be maintained by detecting the degree to which the array of nuclear fuel has been moved in the image captured by the camera.

On the other hand, controlling the position and movement of the moving object (S200) may include measuring a distance between the pipe, the pump, and the outer wall of the nuclear fuel storage tank and the moving object from colliding with each other. At this time, in the step of measuring the mutual distance, a virtual wall may be created to prevent the moving objects from colliding to maintain a safe distance between them.

Accordingly, the step of controlling the position and movement of the moving object based on the mutual distance and the position of the nuclear fuel may be performed.

Meanwhile, in the step of managing the acquired data (S300), the moving object manages, that is, stores and processes the acquired data.

The effects of the apparatus and method for inspecting spent nuclear fuel according to the present invention will be described as follows.

According to at least one of the embodiments of the present invention, by replacing the manual inspection operation method with a robot automation system, it is possible to reduce the radiation exposure of the spent fuel inspector.

In addition, according to at least one of the embodiments of the present invention, it is possible to perform a precise inspection work, there is an advantage that the total inspection period and cost of the spent nuclear fuel can be reduced.

In addition, inspection planning and data management can be systematically operated, and accidents of dropping ICVD equipment into the nuclear fuel storage tank can be prevented.

As another example, in addition to inspection work, it can be used for monitoring the internal condition of the storage tank, and has the advantage of being able to move equipment easily because it is manufactured in a small and light size.

The above detailed description should not be construed as restrictive in all respects and should be considered as illustrative. The scope of the present invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention.

Claims (10)

In the floating robot for the inspection of spent nuclear fuel that has positive buoyancy and is formed to always float on the water of the reservoir,
A water moving body provided with a camera and formed to allow only plane movement; And
Includes; a control unit for sensing the depth of the water in the storage tank, adjusting the focal length of the camera according to the detected depth of water, and controlling the water moving object,
The control unit,
An image processing unit for classifying nuclear fuel stored in the storage tank based on the image captured by the camera;
A position control unit estimating a relative position of the floating body based on the divided nuclear fuel and controlling the position of the floating body based on the estimated relative position;
A navigation unit for controlling the movement of the water moving object; And
And a data management unit that manages the acquired data while the floating body moves.
The method of claim 1,
The position control unit,
The position of the aquatic movable body so that the posture of the aquatic movable body can be maintained by measuring the rotation angle of the floating body using a posture sensor and detecting the direction in which the array of nuclear fuel rotates in the image photographed by the camera. Water robot for inspection of spent nuclear fuel, characterized in that to control the.
The method of claim 1,
The position control unit,
Using an acceleration sensor, the degree of movement of the floating body in a predetermined direction is calculated, and the degree of movement of the array of nuclear fuel in the image captured by the camera is detected, so that the posture of the floating body can be maintained. A water robot for inspection of spent nuclear fuel, characterized in that it controls the position of the floating body.
The method of claim 1,
The control unit,
Connected with a cable to a control equipment separate from the water robot and perform wired communication with the control equipment,
When the amount of rotation of the floating body with respect to the first direction is more than a preset level, the water moving body is rotated in a second direction opposite to the first direction to prevent twisting of the cable. Water robot for
The method of claim 1,
The controller for controlling the operation of the parts provided in the water moving body and the controller disposed at the top of the moving body are located in the upper cylinder,
A floating robot for inspection of spent nuclear fuel, characterized in that it comprises a buoyant material generating the positive buoyancy so that the floating body remains floating on water even when the upper cylinder is submerged.
In the control method of a water robot for inspection of spent nuclear fuel that has positive buoyancy and is formed to always float on the water of the storage tank,
Sensing the depth of water in the storage tank and adjusting a focal length of a camera provided in the water robot according to the detected depth of water;
When the camera moves according to the movement of the floating object provided in the aquatic robot, dividing nuclear fuel stored in the storage tank based on an image captured by the camera;
Estimating a relative position of the floating body based on the divided nuclear fuel;
Controlling the position and movement of the moving object based on the estimated relative position of the moving object; And
And managing the acquired data while the aquatic moving object moves.
The method of claim 6,
Controlling the position and movement of the water moving object,
Using a posture sensor to measure the rotation angle of the water moving object,
A water robot for inspection of spent nuclear fuel, characterized in that it controls the position of the floating body so that the position of the floating body can be maintained by detecting the direction in which the array of nuclear fuel rotates in the image photographed by the camera Control method.
The method of claim 6,
Controlling the position and movement of the water moving object,
The degree to which the moving object has moved in a predetermined direction is calculated using an acceleration sensor,
A water robot for inspection of spent nuclear fuel, characterized in that it controls the position of the water vehicle so that the position of the water vehicle is maintained by detecting the degree of movement of the arrangement of nuclear fuel in the image photographed by the camera Control method.
The method of claim 6,
Controlling the position and movement of the water moving object,
Measuring a distance between the pipe, the pump, and the outer wall in the storage tank and the water moving object from colliding with each other; And
A control method of a floating robot for inspecting spent nuclear fuel comprising the step of controlling the position and movement of the floating body based on the mutual distance and the location of the nuclear fuel.
The method of claim 9,
In the step of measuring the mutual distance, a virtual wall is created to prevent the water moving object from colliding to maintain a safe distance between the pipe, the pump, and the outer wall in the reservoir and the water robot. Control method of a water robot for testing spent fuel.

Images