Device and method for cleaning bottom of nuclear reactor pressure vessel

Abstract

The invention discloses a device and method for cleaning the bottom of a nuclear reactor pressure vessel, the device comprises a workbench, a collector, a telescopic rod, a six-axis mechanical arm and a water inlet pipe, the workbench is separably fixed to a top opening of the pressure vessel and straddles the opening edge of the top opening, the collector is connected to the lower portion of the workbench, and the telescopic rod is connected to the lower portion of the workbench; the upper end of the telescopic rod is fixedly connected with the workbench, and the six-axis mechanical arm is connected to the lower end of the telescopic rod. The collector comprises a submersible pump, the telescopic rod can stretch and deform in the vertical direction to adjust the length, a sweeping tool is arranged at the tail end of the six-axis mechanical arm, one end of the water inlet pipe is connected with the collector, and the other end of the water inlet pipe is connected with the six-axis mechanical arm. By means of the device, the bottom of the nuclear reactor pressure vessel can be cleaned more efficiently, and a good cleaning effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear power plant equipment maintenance, and in particular to a device and method for cleaning the bottom of a nuclear reactor pressure vessel. Background Art

[0002] With the long-term operation of nuclear power units, some impurities and foreign matter may appear at the bottom of the reactor pressure vessel. The presence of these impurities and foreign matter may bring the following negative effects: increase the radiation level around the pressure vessel, and cause damage to other equipment after flowing with the water in the primary circuit. In order to reduce the negative effects, it is necessary to clean the impurities and foreign matter at the bottom of the pressure vessel. However, there is currently a lack of special equipment to clean the bottom of the nuclear reactor pressure vessel. Generally, it is done manually by simply cleaning with a long rod tool erected from the top of the pressure vessel. Not only is the operation efficiency low, but the cleaning effect is also biased. Summary of the invention

[0003] In view of this, one of the purposes of the present invention is to provide a device for cleaning the bottom of a nuclear reactor pressure vessel to improve the operation efficiency and cleaning effect. Another purpose of the present invention is to provide a method for cleaning the bottom of a nuclear reactor pressure vessel using the above device.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A device for cleaning the bottom of a nuclear reactor pressure vessel, comprising:

[0006] A workbench is detachably fixed to the top opening of the pressure vessel and straddles the edge of the top opening;

[0007] A collector connected below the workbench, the collector comprising a submersible pump;

[0008] A telescopic rod, which can be telescopically deformed in the vertical direction to adjust the length, and the upper end of the telescopic rod is fixedly connected to the workbench;

[0009] A six-axis mechanical arm is connected to the lower end of the telescopic rod, and a cleaning tool is provided at the end of the six-axis mechanical arm;

[0010] A water inlet pipe has one end connected to the collector and the other end connected to the six-axis robotic arm.

[0011] Optionally, in the above device, a manipulator capable of grasping is provided at the end of the six-axis manipulator.

[0012] Optionally, in the above device, the telescopic rod includes a plurality of barrel sections, and the water inlet pipe passes through the interior of the barrel sections.

[0013] Optionally, the above device includes a crane disposed on the workbench, and the crane is connected to the movable end of the telescopic rod through a steel wire rope.

[0014] Optionally, in the above device, a support frame is provided near the lower end of the telescopic rod, and the support frame includes:

[0015] A plurality of support rods are evenly distributed around the telescopic rod, and one end of each support rod is hinged to the telescopic rod;

[0016] A telescopic cylinder is connected to the support rod and the telescopic rod, and is used to drive the support rod to rotate relative to the telescopic rod to fold and open the support frame.

[0017] Optionally, in the above device, a bridging block is provided at one end of the support rod away from the telescopic rod, for bridging onto a supporting block on the inner wall of the pressure vessel.

[0018] Optionally, the above device includes a camera and / or an illumination lamp arranged on the six-axis robotic arm.

[0019] Optionally, in the above device, positioning blocks for cooperating with guide columns on the top of the pressure vessel are provided at opposite ends of the workbench.

[0020] Optionally, in the above device, guardrails are provided on two opposite sides of the workbench.

[0021] A method for cleaning the bottom of a nuclear reactor pressure vessel, using the device for cleaning the bottom of a nuclear reactor pressure vessel disclosed in any one of the above, comprising the following steps:

[0022] The workbench is hoisted by a crane, so that the device is hoisted as a whole to the top of the pressure vessel, and the workbench and the pressure vessel are fixedly connected;

[0023] The telescopic rod is extended downward to a predetermined length;

[0024] The submersible pump is started, and the cleaning tool is driven by the six-axis robot arm to clean the target area at the bottom of the pressure vessel, and the foreign matter cleaned by the cleaning is followed by the water flow along the water inlet pipe to reach the collector;

[0025] The submersible pump is turned off, the telescopic rod is retracted upward, the connection between the workbench and the pressure vessel is disassembled, and the workbench is lifted by a crane so that the device is completely separated from the pressure vessel.

[0026] According to the above technical scheme, the device provided by the present invention includes a workbench that can straddle the edge of the top opening of the pressure vessel, which is detachably fixedly connected to the pressure vessel, a collector with a submersible pump is connected below the workbench, and a six-axis mechanical arm is connected through a telescopic rod. At the same time, a cleaning tool is provided at the end of the six-axis mechanical arm, one end of the water inlet pipe is connected to the collector, and the other end is connected to the six-axis mechanical arm. When cleaning the bottom of the nuclear reactor pressure vessel, the telescopic rod sends the six-axis mechanical arm at its lower end to the bottom of the pressure vessel through elongation and deformation. The six-axis mechanical arm can flexibly move the cleaning tool along the bottom surface of the pressure vessel. After the cleaning tool cleans the foreign matter at the bottom of the pressure vessel, the foreign matter is mixed in the water and sucked into the water inlet pipe, and reaches the collector along the water inlet pipe with the water flow. It can be seen that the use of the device of the present invention to clean the bottom of the nuclear reactor pressure vessel realizes the mechanization of the operation and greatly improves the operation efficiency. Moreover, the mechanized operation can clean the target area at the bottom of the pressure vessel more comprehensively, which is conducive to improving the cleaning effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0028] Figure 1 is a schematic diagram of a device for cleaning the bottom of a nuclear reactor pressure vessel provided by an embodiment of the present invention;

[0029] Figure 2 yes Figure 1 Bottom view of

[0030] Figure 3 The present invention is a schematic diagram of the use status of the device for cleaning the bottom of a nuclear reactor pressure vessel provided by an embodiment of the present invention.

[0031] The markings in the figure are:

[0032] 1. Workbench; 11. Positioning block; 2. Crane; 3. Telescopic rod; 4. Telescopic cylinder; 5. Support rod; 6. Six-axis robotic arm; 7. Robot; 8. Cleaning tool; 9. Collector; 200. Pressure vessel. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] See also Figure 1~Figure 3 The embodiment of the present invention provides a device for cleaning the bottom of a nuclear reactor pressure vessel, comprising a workbench 1, a collector 9, a telescopic rod 3, a six-axis robot arm 6 and a water inlet pipe (not shown in the figure), wherein the workbench 1 is detachably fixed to the top of the pressure vessel 200 and straddles the edge of the top, the collector 9 is connected to the bottom of the workbench 1, the upper end of the telescopic rod 3 is fixedly connected to the workbench 1, and the six-axis robot arm 6 is connected to the lower end of the telescopic rod 3. The collector 9 includes a submersible pump, the telescopic rod 3 can be telescopically deformed in the vertical direction to adjust the length, a cleaning tool 8 is provided at the end of the six-axis robot arm 6, and one end of the water inlet pipe is connected to the collector 9, and the other end is connected to the six-axis robot arm 6.

[0035] Before cleaning the bottom of the pressure vessel 200, the top cover of the pressure vessel 200 and the internal facilities (such as the core, etc.) have been removed, that is, the pressure vessel 200 is in an open state and the internal facilities have been emptied. The workbench 1 is the main load-bearing part of the device of the present invention. Other facilities of the device can be installed on the workbench 1. When the device is hoisted as a whole by a crane, only the hanging connection points can be taken on the workbench 1, as long as the workbench 1 can be kept horizontal during the hoisting process. When it is necessary to clean the bottom of the pressure vessel 200, first hoist the device of the present invention as a whole to the top of the pressure vessel 200, such as Figure 3 As shown, the workbench 1 straddles the edge of the top opening, the workbench 1 is located above the water level of the pressure vessel 200, and the collector 9 below the workbench 1 is located below the water level of the pressure vessel 200, ensuring that the submersible pump of the collector 9 can function. The telescopic rod 3 is located below the workbench 1, and the function of the telescopic rod 3 is to send the six-axis robot arm 6 at its lower end to the bottom of the pressure vessel 200 through elongation and deformation, ensuring that the cleaning tool 8 at the end of the six-axis robot arm 6 can perform cleaning operations at the bottom of the pressure vessel 200.

[0036] There are many options for the specific structural form of the cleaning tool 8. A commercially available tool that can clean foreign matter at the bottom of the pressure vessel 200 can be used. For example, the cleaning tool 8 can be a sweeping disc with a brush. The six-axis robot 6 is an existing mature product, so its structure and movement principle are not described in detail here. It is easy to understand that the six-axis robot 6 can flexibly move the cleaning tool 8 along the bottom surface of the pressure vessel 200. For example, in the arc-shaped part of the bottom surface, the six-axis robot 6 can move the cleaning tool 8 along the arc-shaped trajectory. After the cleaning tool 8 cleans the foreign matter at the bottom of the pressure vessel 200, the foreign matter is mixed in the water and sucked into the water inlet pipe, and reaches the collector 9 along the water inlet pipe with the water flow. The suction force of the water inlet pipe on the foreign matter is generated by the submersible pump in the starting state, that is, under the action of the submersible pump, water flows from the water inlet pipe into the collector 9, and then flows out from the water outlet of the collector 9. It should be noted that a filter element is provided in the collector 9 to prevent foreign matter from reaching the submersible pump. That is to say, after the foreign matter reaches the collector 9 along the water inlet pipe with the water flow, the foreign matter is intercepted by the filter element and stays in the collector 9 .

[0037] The device of the present invention is used to clean the bottom of the nuclear reactor pressure vessel, which realizes the mechanization of the operation, greatly improves the operation efficiency, and can more comprehensively clean the target area at the bottom of the pressure vessel. For example, the six-axis robot 6 drives the cleaning tool 8 to travel through various parts of the target area at the bottom of the pressure vessel 200 according to the set movement trajectory program. The bottom of the pressure vessel 200 is generally spherical, and when cleaning, it can be cleaned from the edge to the center in circles. In each circle, the cleaning tool 8 can first move from the outside to the inside along the radial direction, and then move to the next position of the circle along the circumferential direction, and so on, until all parts of the circle are cleaned.

[0038] In some embodiments, the end of the six-axis robot arm 6 may be provided with a manipulator 7 capable of grasping, and the manipulator 7 is used to grasp larger foreign objects. The manipulator 7 may be set as a three-claw structure, or it may be set as a structure of two clamps, that is, the two clamps are close to and away from each other to achieve grasping and releasing. Of course, the manipulator 7 may also adopt other structural forms, which are not limited by the present invention. In order to achieve more refined cleaning operations, a camera may be set on the six-axis robot arm 6, and the camera transmits the captured image to a remote workstation, so that the worker can understand the situation at the bottom of the pressure vessel 200 through the monitor of the workstation, thereby controlling the six-axis robot arm 6 to better complete the cleaning operation. On this basis, a lighting lamp may be set on the six-axis robot arm 6 to improve the brightness of the environment at the bottom of the pressure vessel 200, so that the camera can take clearer pictures.

[0039] There are many options for the structure of the telescopic rod 3. In some embodiments, the telescopic rod 3 may include multiple barrel sections, and the water inlet pipe passes through the inside of the barrel section. Adjacent barrel sections are slidably connected, so that the telescopic rod 3 has a telescopic function. The barrel section has a hollow channel that can be used to lay the water inlet pipe. In order to adapt to the telescopic deformation of the telescopic rod 3, the water inlet pipe can be set as a flexible bendable pipe, or can be set as a corrugated pipe that can be extended and shortened.

[0040] In some embodiments, a crane 2 may be provided on the workbench 1, and the crane 2 is connected to the movable end of the telescopic rod 3 through a steel wire rope, and the crane 2 provides telescopic power for the telescopic rod 3. It is easy to understand that when the crane 2 reels the steel wire rope, the movable end of the telescopic rod 3 is pulled upward to shorten the telescopic rod 3. When the crane 2 releases the steel wire rope, the movable end of the telescopic rod 3 moves downward under the gravity of the lower equipment (six-axis mechanical arm 6, etc.), so that the telescopic rod 3 is extended. In order to improve safety, the crane 2 may be provided with a tension sensor and a limit sensor. The tension sensor is used to detect the current tension of the steel wire rope, and the limit sensor is triggered when the steel wire rope is released to a certain length. Of course, in other embodiments, the telescopic power for the telescopic rod 3 may be provided in other forms. For example, a hydraulic drive system may be provided on the workbench 1, and connected to the telescopic rod 3 through a hydraulic pipeline. The telescopic rod 3 is extended and shortened under the action of the hydraulic pressure. In this structure, the telescopic rod 3 as a whole can be understood as a hydraulic cylinder.

[0041] In some embodiments, the device may include a support frame arranged near the lower end of the telescopic rod 3, the support frame including a support rod 5 and a telescopic cylinder 4, wherein the support rod 5 is multiple and evenly distributed around the telescopic rod 3, and one end of the support rod 5 is hinged to the telescopic rod 3; the telescopic cylinder 4 connects the support rod 5 and the telescopic rod 3, and is used to drive the support rod 5 to rotate relative to the telescopic rod 3 to fold and open the support frame. Figure 1 and Figure 3 , the telescopic cylinder 4 and the support rod 5 form a structure similar to the ribs of an umbrella, which can be opened and folded flexibly. It is easy to understand that when the telescopic cylinder 4 is extended, the support rod 5 is pushed away from the telescopic rod 3 to spread the support rod 5; when the telescopic cylinder 4 is shortened, the support rod 5 is pulled toward the telescopic rod 3 to close the support rod 5. After the support frame is opened, the support rod 5 cooperates with the structure in the pressure vessel 200 to form a supporting force, so that the device as a whole can be more stably maintained on the pressure vessel 200, so that the six-axis robot 6 can move the position more accurately.

[0042] In some embodiments, a lap block may be provided at one end of the support rod 5 away from the telescopic rod 3, which is used to be placed on the support block of the inner wall of the pressure vessel 200. It should be noted that the support block of the inner wall of the pressure vessel 200 is an auxiliary structure of the pressure vessel 200 itself, and provides a mounting point for other facilities in the pressure vessel 200. The device of the present invention uses the support block originally existing in the pressure vessel 200 to cooperate with the support rod 5, which can provide a larger support force without affecting other parts of the inner wall of the pressure vessel 200. Since the lap block at the end of the support rod 5 is placed on the support block of the inner wall of the pressure vessel 200, it is easy to understand that when the telescopic cylinder 4 is extended, the support rod 5 is rotated downward relative to the telescopic rod 3, and conversely, when the telescopic cylinder 4 is shortened, the support rod 5 is rotated upward relative to the telescopic rod 3. Of course, in other embodiments, the support frame can also be set to allow the support rod 5 to rotate upward relative to the telescopic rod 3 when the telescopic cylinder 4 is extended, as long as the support frame after opening can form the required support force between the support rod 5 and the pressure vessel 200. In addition, the angular range of rotation of the support rod 5 relative to the telescopic rod 3 under the action of the telescopic cylinder 4 can be set as needed, for example, it can be set to 90°, so that the support rod 5 can be rotated to a state perpendicular to the telescopic rod 3, such as Figure 1 shown.

[0043] See also Figure 2 and Figure 3 In some embodiments, the opposite ends of the workbench 1 may be provided with positioning blocks 11 for cooperating with the guide columns on the top of the pressure vessel 200. The guide columns are installed on the edge of the top opening of the pressure vessel 200 to guide the workbench 1 to sit on the top opening of the pressure vessel 200, which can improve the efficiency of the lifting operation. Moreover, the cooperation between the guide columns and the positioning blocks 11 limits the rotation of the workbench 1 relative to the pressure vessel 200, which is beneficial to improve the stability of the workbench 1 after it is installed on the pressure vessel 200. The positioning block 11 may be provided with a round hole to cooperate with the guide column, or a semicircular hole to cooperate with the guide column. The present invention does not limit the cooperation structure of the positioning block 11 and the guide column. See Figure 1 and Figure 3 In some embodiments, guardrails may be provided on opposite sides of the workbench 1 , and the guardrails may improve the safety of workers walking on the workbench 1 .

[0044] Based on the device for cleaning the bottom of a nuclear reactor pressure vessel provided by the present invention, the present invention also provides a method for cleaning the bottom of a nuclear reactor pressure vessel, comprising the following steps:

[0045] S1, the workbench 1 is hoisted by a crane, and the device is hoisted as a whole to the top of the pressure vessel 200, and the workbench 1 and the pressure vessel 200 are fixedly connected.

[0046] The crane is an infrastructure built in the nuclear power plant, and the user hoists the equipment. When the device of the present invention is used for cleaning operations, the crane is responsible for hoisting the device to the top of the pressure vessel 200, and after the operation is completed, the device is transported back to the original position for next use. Figure 2 and Figure 3 As shown, the inner wall at the top of the pressure vessel 200 is provided with a step structure, and the arc-shaped end of the workbench 1 is seated on the step structure. The workbench 1 and the pressure vessel 200 can be fixedly connected by, for example, bolts.

[0047] S2, the telescopic rod 3 is extended downward to a predetermined length.

[0048] The telescopic rod 3 is extended downward so that the six-axis robot arm 6 reaches near the bottom of the pressure vessel 200, which satisfies the cleaning tool 8 to perform the cleaning operation. It is easy to understand that the predetermined length to which the telescopic rod 3 is extended is set according to the size of the pressure vessel 200.

[0049] S3, the submersible pump is started, and the cleaning tool 8, driven by the six-axis robot arm 6, cleans the target area at the bottom of the pressure vessel 200, and the foreign matter cleaned up follows the water flow along the water inlet pipe to the collector 9.

[0050] After the submersible pump of the collector 9 is started, the water in the pressure vessel 200 is sucked into the water inlet pipe and transported to the collector 9. During this process, the foreign matter swept away enters the collector 9 with the water flow, and the foreign matter is intercepted by the filter element in the collector 9 and finally remains in the collector 9. The water entering the collector 9 through the water inlet pipe is finally returned to the pressure vessel 200 again under the action of the submersible pump.

[0051] S4, the submersible pump is turned off, the telescopic rod 3 is retracted upward, the connection between the workbench 1 and the pressure vessel 200 is disassembled, and the workbench 1 is lifted by a crane so that the entire device leaves the pressure vessel 200.

[0052] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0053] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for cleaning the bottom of a nuclear reactor pressure vessel, comprising: A workbench is detachably fixed to the top opening of the pressure vessel and straddles the edge of the top opening; A collector connected below the workbench, the collector comprising a submersible pump; A telescopic rod, which can be telescopically deformed in the vertical direction to adjust the length, and the upper end of the telescopic rod is fixedly connected to the workbench; A six-axis mechanical arm is connected to the lower end of the telescopic rod, and a cleaning tool is provided at the end of the six-axis mechanical arm; A water inlet pipe has one end connected to the collector and the other end connected to the six-axis robotic arm.

2. The device according to claim 1, characterized in that A manipulator capable of grasping is arranged at the end of the six-axis manipulator.

3. The device according to claim 1, characterized in that The telescopic rod comprises a plurality of barrel sections, and the water inlet pipe passes through the interior of the barrel sections.

4. The device according to claim 1, characterized in that It comprises a crane arranged on the workbench, and the crane is connected with the movable end of the telescopic rod through a steel wire rope.

5. The device according to claim 1, characterized in that It includes a support frame arranged near the lower end of the telescopic rod, and the support frame includes: A plurality of support rods are evenly distributed around the telescopic rod, and one end of each support rod is hinged to the telescopic rod; A telescopic cylinder is connected to the support rod and the telescopic rod, and is used to drive the support rod to rotate relative to the telescopic rod to fold and open the support frame.

6. The device according to claim 5, characterized in that A bridging block is provided at one end of the support rod away from the telescopic rod, and is used for bridging onto the supporting block on the inner wall of the pressure vessel.

7. The device according to claim 1, characterized in that It includes a camera and / or an illuminator arranged on the six-axis robotic arm.

8. The device according to any one of claims 1 to 7, characterized in that: Positioning blocks for cooperating with the guide columns on the top of the pressure vessel are arranged at opposite ends of the workbench.

9. The device according to claim 8, characterized in that Guardrails are arranged on two opposite sides of the workbench.

10. A method for cleaning the bottom of a nuclear reactor pressure vessel, using the device for cleaning the bottom of a nuclear reactor pressure vessel as claimed in any one of claims 1 to 9, comprising the following steps: The workbench is hoisted by a crane, so that the device is hoisted as a whole to the top of the pressure vessel, and the workbench and the pressure vessel are fixedly connected; The telescopic rod is extended downward to a predetermined length; The submersible pump is started, and the cleaning tool is driven by the six-axis robot arm to clean the target area at the bottom of the pressure vessel, and the foreign matter cleaned by the cleaning is followed by the water flow along the water inlet pipe to reach the collector; The submersible pump is turned off, the telescopic rod is retracted upward, the connection between the workbench and the pressure vessel is disassembled, and the workbench is lifted by a crane so that the device is completely separated from the pressure vessel.

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