A reactor irregular floor drain plugging device

Abstract

The present invention belongs to the maintenance of nuclear power plant reactors, and specifically relates to a reactor irregular floor drain plugging device, including a sealing pressure plate, a fixed lower plate, a fixed upper plate, a fixed screw, a sealing screw and a sealing screw ball head; the sealing screw is coaxially arranged in the fixed screw, the fixed screw passes through the light hole in the center of the fixed upper plate, and the bottom of the fixed screw is welded and fixed to the upper surface of the fixed lower plate; a fixed rubber ring is arranged between the edges of the fixed upper plate and the fixed lower plate; a sealing rubber ring is arranged at the bottom of the edge of the sealing pressure plate. It can achieve effective plugging of irregular floor drains, and avoid the main bolt loosening agent sprayed during the unsealing of the reactor pressure vessel accidentally flowing into the isolation bellows floor drain, resulting in the occurrence of an event that the residual loosening agent cannot be effectively discharged from the floor drain and the water quality of the reactor primary circuit is polluted.

Description

Technical Field

[0001] The invention belongs to the maintenance of nuclear power plant reactors, and in particular relates to a floor drain plugging device. Background Art

[0002] The seal between the reactor pressure vessel and the upper assembly cover of a large nuclear power plant is achieved through the cooperation of the main bolts, main nuts, hemispherical gaskets and nickel washers. The sealing principle is to use a bolt tensioning machine to stretch the main bolts and ensure the sealing of the upper assembly cover under the action of the bolt pre-tightening force.

[0003] When using a bolt tensioner to screw the main bolt into the main bolt hole, a layer of lubricant needs to be applied to the threaded parts of the main bolt, main nut and main bolt hole. After a fuel cycle, the nuclear reactor needs to be overhauled and some new fuel assemblies need to be replaced. The reactor pressure vessel, as a storage container for fuel assemblies, must be opened. However, due to a fuel cycle, the long-term high temperature environment causes the lubricant between the main bolt and the pressure vessel bolt hole and the main bolt and the main nut to dry out. Even using a bolt tensioner cannot ensure that the main bolt is screwed out smoothly. In order to ensure that the main bolts and main nuts on the main joint surface of the reactor pressure vessel are screwed out smoothly, a large amount of bolt loosening agent needs to be sprayed between the main bolt and the bolt hole, and between the main bolt and the main nut thread during each refueling overhaul. In addition to penetrating into the threaded parts between the main bolt and the bolt hole, and between the main bolt and the main nut, a large amount of bolt loosening agent will flow along the surface of the main bolt and the main nut to the isolation corrugated section at the main joint surface of the pressure vessel.

[0004] Three irregular floor drains are set in the isolation bellows of the main joint surface of the reactor pressure vessel, which are mainly used to drain the residual primary circuit water in the isolation bellows of the main joint surface of the reactor shaft after each rise and fall of the water level in the reactor shaft. In the past overhaul, when the water level in the reactor shaft rose, after the water level overflowed the isolation bellows of the main joint surface of the reactor pressure vessel, there was a phenomenon of white emulsified substances floating in the primary circuit water. After on-site sampling and analysis, the white emulsion contained main bolt loosening agent components. Through the review and analysis of the maintenance work during the overhaul, the main bolt loosening agent is mainly used to spray the main bolts and main nuts during the unsealing of the reactor pressure vessel. Although the staff will wipe the residual loosening agent at the isolation bellows at the main joint surface of the pressure vessel after each spraying of the main bolt loosening agent, a small amount of bolt loosening agent may still flow into the floor drain in the isolation bellows and cannot be discharged. After this incident, the two units of the first phase of the Tianwan Nuclear Power Plant used cement and absorbent paper to seal and wipe the floor drains during the subsequent overhaul, but this did not fundamentally solve the problem that a small amount of main bolt loosening agent still seeped into the floor drain and could not be discharged. As a result, when the water level of the reactor shaft was raised or lowered, the water quality of the reactor primary circuit was occasionally contaminated by the main bolt loosening agent remaining in the floor drain. After analysis, there are currently no effective methods to seal this type of floor drain. There are two reasons:

[0005] 1. This type of floor drain is irregular in shape: the whole is circular, with a guide groove on the side, and the bottom of the guide groove is on the same plane as the bottom of the floor drain. This irregular shape makes it impossible to block the non-circular side of the floor drain;

[0006] 2. This type of floor drain is located on the isolation bellows of the main joint surface of the reactor pressure vessel. The isolation bellows of the main joint surface of the reactor pressure vessel are nuclear-grade equipment and cannot be mechanically modified by drilling holes to provide a force point for the bottom surface of the floor drain. Therefore, it is impossible to seal the circular bottom surface of the floor drain.

[0007] In summary, there is currently no suitable sealing method to effectively seal the irregular floor drain when the loosening agent is sprayed on the main bolts, which causes the bolt loosening agent to seep into the floor drain and then pollute the water quality of the reactor primary circuit. Summary of the invention

[0008] The purpose of the present invention is to provide a reactor irregular floor drain plugging device to achieve effective plugging of the irregular floor drain and prevent main bolt loosening agent from flowing into the floor drain to pollute the reactor primary circuit water quality.

[0009] The technical solution of the present invention is as follows:

[0010] A reactor irregular floor drain plugging device comprises a sealing pressure plate at the bottom, a fixed lower plate arranged above the sealing pressure plate, a fixed upper plate arranged above the fixed lower plate, a fixed screw with its lower end installed at the center of the fixed upper plate, a sealing screw coaxially installed in the fixing screw and with its lower end passing through the center of the fixed lower plate, and a sealing screw ball head at the lower end of the sealing screw; the sealing screw is coaxially arranged in the fixing screw, the fixing screw passes through the light hole in the center of the fixed upper plate, and the bottom of the fixing screw is welded and fixed to the upper surface of the fixed lower plate; a fixing rubber ring is arranged between the edges of the fixed upper plate and the fixed lower plate; a sealing rubber ring is arranged at the bottom of the edge of the sealing pressure plate.

[0011] The edge of the fixed upper plate has a side wall extending downward, thereby forming an inner concave platform of the fixed upper plate at the bottom of the fixed upper plate; the side wall extends downward to form an annular fixed pressure leg; the edge of the fixed lower plate is processed with a lip plate extending horizontally outward to form an annular outer concave platform of the fixed lower plate, so that the side of the fixed lower plate forms a stepped structure, and the center of the fixed lower plate forms an outer convex platform of the fixed lower plate; the fixed rubber ring is located between the annular fixed pressure leg and the annular outer concave platform of the fixed lower plate.

[0012] The outer protrusion of the fixed lower plate is located in the inner concave platform of the fixed upper plate.

[0013] The bottom center of the fixed lower plate is processed with a circular fixed lower plate inner concave platform; the center of the upper surface of the sealing pressure plate is processed with an upwardly protruding circular platform to form a sealing pressure plate outer convex platform, and the sealing pressure plate outer convex platform is located inside the fixed lower plate inner concave platform.

[0014] A spherical groove is processed at the center of the outer boss of the sealing pressure plate, and the lower part of the sealing screw ball head is located in the spherical groove.

[0015] The outer edge of the bottom of the sealing pressure plate is processed with an annular groove for fixing and limiting the sealing rubber ring.

[0016] A dovetail knob is provided on the top of the sealing screw, and its appearance is a dovetail shape, and is connected to the head of the sealing screw by welding.

[0017] The middle part of the sealing screw is an external thread structure, which is installed in the middle of the fixing screw by cooperating with the fixing screw and the internal thread at the center of the fixing lower plate.

[0018] The exterior of the fixing screw rod is an external thread structure, and a fixing nut is arranged on the exterior of the fixing screw rod.

[0019] The fixing nut is a hexagonal nut, and tightening the fixing nut applies a downward force to the fixed upper plate.

[0020] It is located above the floor drain bottom plate, the floor drain bottom plate is processed with a floor drain flow hole, and the sealing rubber ring is in contact with the floor drain bottom plate.

[0021] It is located on the inner side of the floor drain side plate, and the inner surface of the floor drain side plate is in contact with the sealing rubber ring and the fixing rubber ring.

[0022] A guide groove is arranged on the outside thereof, wherein the guide groove is provided with a vertical plate and a horizontal plate, wherein the vertical plate is in contact with the sealing rubber ring and the fixing rubber ring, and the horizontal plate extends outward.

[0023] The remarkable effects of the present invention are as follows: the irregular floor drain can be effectively blocked without machining the existing nuclear-grade equipment, and the main bolt loosening agent sprayed during the unsealing of the reactor pressure vessel is prevented from accidentally flowing into the isolation bellows floor drain, resulting in the floor drain being unable to effectively discharge the residual loosening agent and contaminating the reactor primary circuit water quality.

[0024] This device does not seal on the side like the existing sealing method, but seals from the bottom of the floor drain. By providing a force point by itself, a sealing device can complete the sealing and sealing of the floor drain and the guide groove.

[0025] The floor drain plugging device is an integrated structure, and the various components are mechanically matched through threads, etc., which is easy to operate and has no foreign body risk;

[0026] The method of sealing the bottom surface of the floor drain overcomes the difficulty of the irregular shape of the side of the floor drain;

[0027] The fixing rubber ring expands by screwing its own fixing nut, thereby providing a force point for the sealing at the bottom of the floor drain, without the need for additional drilling or other mechanical processing;

[0028] The fixed pressing leg cooperates with the outer boss of the fixed lower plate to provide a fixed position for the fixed rubber ring, play a limiting role, and prevent the rubber ring from moving or coming off;

[0029] The sealing platen is designed as an outer convex platform, which increases the thickness of the sealing platen. By cooperating with the inner concave platform of the fixed lower plate, it not only saves the space of the entire device, but also improves the mechanical strength of the sealing platen.

[0030] The outer boss of the sealing pressure plate is processed with a spherical groove, which can cooperate with the ball head at the bottom of the sealing screw, so that the sealing pressure plate can be connected to the entire device as a whole to avoid the process of disassembly and assembly; and when the sealing screw is screwed, only an axial downward force is applied to the sealing pressure plate to avoid the friction of the screwing causing the sealing pressure plate to rotate, resulting in the risk of the sealing rubber ring being squeezed out;

[0031] The bottom of the sealing plate is designed with an annular groove around it, which matches the shape of the sealing rubber ring and can provide precise positioning for the sealing rubber ring to prevent the rubber ring from moving;

[0032] The sealing screw and the fixed screw are integrated through thread matching. At the same time, a dovetail knob is processed on the head of the sealing screw to facilitate direct manual operation by personnel and avoid the risks caused by the use of additional tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of a reactor irregular floor drain plugging device;

[0034] Figure 2 This is a schematic diagram of the use of the reactor irregular floor drain plugging device;

[0035] In the figure: 1. dovetail knob; 2. sealing screw; 3. fixing screw; 4. fixing nut; 5. fixing upper plate; 6. fixing lower plate; 7. fixing rubber ring; 8. sealing pressure plate; 9. annular groove; 10. light hole; 11. fixing inner concave platform of upper plate; 12. sealing screw ball head; 13. spherical groove; 14. fixing outer boss of lower plate; 15. fixing pressure leg; 16. fixing inner concave platform of lower plate; 17. sealing pressure plate outer boss; 18. sealing rubber ring; 19. fixing outer concave platform of lower plate; 20. floor drain leakage hole; 21. guide groove; 22. floor drain side plate. DETAILED DESCRIPTION

[0036] The present invention will be further described below through the accompanying drawings and specific implementation methods.

[0037] like Figure 1 As shown, the device includes a sealing pressure plate 8 at the bottom, a fixed lower plate 6 above the sealing pressure plate 8, a fixed upper plate 5 above the fixed lower plate 6, a fixed screw 3 with its lower end installed at the center of the fixed upper plate 5, a sealing screw 2 coaxially installed in the fixed screw 3 and with its lower end passing through the center of the fixed lower plate 6, a sealing screw ball head 12 installed at the lower end of the sealing screw 2, a fixing nut 4 sleeved on the outside of the fixed screw 3, and a dovetail knob 1 installed on the top of the sealing screw 2.

[0038] The following describes in detail how to install each part.

[0039] (1) The dovetail knob 1 is in the shape of a dovetail and is connected to the head of the sealing screw 2 by welding.

[0040] (2) A dovetail knob 1 is welded to the head of the sealing screw 2; the middle part is an external thread structure, which is installed in the middle of the fixing screw 3 by cooperating with the internal threads in the center of the fixing screw 3 and the fixing lower plate 6; and a sealing screw ball head 12 is welded to the bottom.

[0041] (3) The exterior of the fixing screw 3 is an external thread structure, which cooperates with the internal thread of the fixing nut 4; the center is processed with an internal thread and cooperates with the external thread of the sealing screw 2; the fixing screw 3 passes through the light hole 10 in the center of the fixed upper plate 5, and the bottom of the fixing screw 3 is installed on the upper surface of the fixed lower plate 6 by welding.

[0042] (4) The fixing nut 4 is a hexagonal nut, which cooperates with the external thread of the fixing screw 3 and applies a downward force to the fixing upper plate 5 when the fixing nut 4 is screwed.

[0043] (5) A light hole 10 is machined in the middle of the fixed upper plate 5 for passing the fixing screw 3;

[0044] The edge of the fixed upper plate 5 has a side wall extending downward, thereby forming an inner concave platform 11 of the fixed upper plate at the bottom of the fixed upper plate 5, which is used to accommodate the outer protrusion 14 of the fixed lower plate; the side wall extends downward to form an annular fixed pressure leg 15, which can squeeze the fixed rubber ring 7 between the fixed upper plate 5 and the fixed lower plate 6 downward.

[0045] (6) A lip plate extending horizontally outward is processed around the edge of the fixed lower plate 6 to form an annular fixed lower plate outer concave platform 19, so that the side of the fixed lower plate 6 forms a stepped structure, and a fixed lower plate outer boss 14 is formed in the center of the fixed lower plate 6. An internal threaded hole is processed in the center of the fixed lower plate outer boss 14, and the lower end of the fixing screw 3 is installed by threading.

[0046] The entire outer protrusion 14 of the fixed lower plate is placed in the inner concave platform 11 of the fixed upper plate to form a fit.

[0047] The outer concave platform 19 of the annular fixed lower plate is provided with a fixed rubber ring 7;

[0048] A circular fixed lower plate inner concave platform 16 is processed at the bottom center of the fixed lower plate 6 to accommodate the sealing pressure plate outer convex platform 17 in the lower sealing pressure plate 8.

[0049] (7) A convex cone protruding upward is processed at the center of the upper surface of the sealing pressure plate 8 to form an outer boss 17 of the sealing pressure plate. The outer boss 17 of the sealing pressure plate is located inside the inner recess 16 of the fixed lower plate, and a spherical groove 13 is processed at the center of the outer boss 17 of the sealing pressure plate. The lower end of the sealing screw 2 is fixedly installed with a sealing screw ball head 12. The lower part of the sealing screw ball head 12 is located in the spherical groove 13. The two are lubricated and can move relative to each other. An annular groove 9 is processed at the outer edge of the bottom of the sealing pressure plate 8 for fixing and limiting the sealing rubber ring 18.

[0050] like Figure 2 As shown, during the unsealing of the reactor pressure vessel, the floor drain plugging device is used to plug the three floor drains at the isolation bellows at the main joint surface of the pressure vessel before spraying a large amount of thread loosening agent between the main bolts and the bolt holes, and between the main bolts and the main nuts.

[0051] like Figure 2As shown, the floor drain bottom plate where the floor drain leakage hole 20 is located is located at the lower part of the floor drain sealing device, and its upper surface contacts the lower part of the sealing rubber ring 18. The floor drain side plate 22 is located on one side of the floor drain sealing device, and its inner surface contacts the sealing rubber ring 18 and the fixed rubber ring 7.

[0052] The above-mentioned guide groove 21 is located at the other side of the floor drain plugging device, and its vertical plate is in contact with the sealing rubber ring 18 and the fixed rubber ring 7, and the horizontal plate extends outward.

[0053] The floor drain hole 20 is located on the floor drain bottom plate.

[0054] The specific steps of using the above device are as follows:

[0055] (1) Loosen the fixing nut 4 by hand, put the fixing rubber ring 7 on the outer concave platform 19 of the fixed lower plate, and then place the sealing rubber ring 18 on the bottom surface of the floor drain;

[0056] (2) Loosen the dovetail knob 1 by hand and place the floor drain plugging device stably in the floor drain so that the annular groove 9 of the sealing pressure plate 8 is pressed on the sealing rubber ring 18;

[0057] (3) Use a wrench to tighten the fixing nut 4. The internal thread of the fixing nut 4 cooperates with the external thread of the fixing screw 3 to apply a downward force to the fixed upper plate 5 and the fixed pressure leg 15. The downward force acts on the fixed rubber ring 7 through the fixed pressure leg 15. The fixed rubber ring 7 is expanded by the mutual compression of the fixed pressure leg 15 and the outer concave platform 19 of the fixed lower plate, so that it is tightly attached to the floor drain side plate 22, providing a stable friction force and force point for the sealing pressure plate 8;

[0058] (4) Tighten the dovetail knob 1 at the head of the sealing screw 2 by hand, and the external thread of the sealing screw 2 cooperates with the internal thread between the fixed screw 3 and the fixed lower plate 6, and the friction force of the fixed rubber ring 7 is used as a fulcrum to make the sealing screw 2 move downward, thereby driving the sealing screw ball head 12 to rotate and move downward;

[0059] (5) The sealing screw ball head 12 cooperates with the spherical groove 13 on the outer boss 17 of the sealing pressure plate. Since there is a gap between the sealing screw ball head 12 and the spherical groove 13, and they lubricate each other, when the sealing screw ball head 12 rotates, the sealing pressure plate 8 does not rotate with it. At this time, the sealing screw ball head 12 applies a downward force to the outer boss 17 of the sealing pressure plate, and the downward force is then evenly applied to the sealing pressure plate 8 by the outer boss 17 of the sealing pressure plate, so that the annular groove 9 squeezes the sealing rubber ring 18 downward, thereby achieving sealing of the bottom surface of the floor drain, and when the liquid flows to the floor drain through the guide groove 21, it can be effectively blocked.

Claims

1. A reactor irregular floor drain plugging device, characterized in that: The invention comprises a sealing pressure plate (8) located at the bottom, a fixed lower plate (6) arranged above the sealing pressure plate (8), a fixed upper plate (5) arranged above the fixed lower plate (6), a fixed screw (3) whose lower end is installed at the center of the fixed upper plate (5), a sealing screw (2) coaxially installed in the fixed screw (3) and whose lower end passes through the center of the fixed lower plate (6), and a sealing screw ball head (12) located at the lower end of the sealing screw (2); the sealing screw (2) is coaxially arranged in the fixed screw (3), the fixed screw (3) passes through the light hole (10) in the center of the fixed upper plate (5), and the bottom of the fixed screw (3) is welded and fixed to the upper surface of the fixed lower plate (6); a fixed rubber ring (7) is arranged between the edges of the fixed upper plate (5) and the fixed lower plate (6); and a sealing rubber ring (18) is arranged at the bottom of the edge of the sealing pressure plate (8).

2. A reactor irregular floor drain plugging device as claimed in claim 1, characterized in that: The edge of the fixed upper plate (5) has a side wall extending downward, thereby forming an inner concave platform (11) of the fixed upper plate at the bottom of the fixed upper plate (5); the side wall extends downward to form an annular fixed pressure leg (15); the edge of the fixed lower plate (6) is processed with a lip plate extending horizontally outward to form an annular fixed lower plate outer concave platform (19), so that the side of the fixed lower plate (6) forms a stepped structure, and the center of the fixed lower plate (6) forms a fixed lower plate outer convex platform (14); the fixed rubber ring (7) is located between the annular fixed pressure leg (15) and the annular fixed lower plate outer concave platform (19).

3. A reactor irregular floor drain plugging device as claimed in claim 2, characterized in that: The fixed lower plate outer protrusion (14) is located inside the fixed upper plate inner concave platform (11).

4. A reactor irregular floor drain plugging device as claimed in claim 1, characterized in that: The bottom center of the fixed lower plate (6) is processed with a circular fixed lower plate inner concave platform (16); the center of the upper surface of the sealing pressure plate (8) is processed with an upwardly protruding circular platform to form a sealing pressure plate outer boss (17), and the sealing pressure plate outer boss (17) is located inside the fixed lower plate inner concave platform (16).

5. A reactor irregular floor drain plugging device as claimed in claim 4, characterized in that: A spherical groove (13) is processed at the center of the outer boss (17) of the sealing pressure plate, and the lower part of the sealing screw ball head (12) is located in the spherical groove (13).

6. A reactor irregular floor drain plugging device as claimed in claim 1, characterized in that: An annular groove (9) is machined on the outer edge of the bottom of the sealing pressure plate (8).

7. A reactor irregular floor drain plugging device as claimed in claim 1, characterized in that: The top of the sealing screw (2) is provided with a dovetail knob (1), which has a dovetail shape and is fixed to the head of the sealing screw (2).

8. A reactor irregular floor drain plugging device as claimed in claim 1, characterized in that: The middle part of the sealing screw (2) is an external thread structure, which is installed in the middle of the fixing screw (3) by cooperating with the internal thread of the fixing screw (3) and the center of the fixing lower plate (6).

9. A reactor irregular floor drain plugging device as claimed in claim 1, characterized in that: The exterior of the fixing screw rod (3) is an external thread structure, and a fixing nut (4) is arranged on the exterior thereof.

10. A reactor irregular floor drain plugging device as claimed in claim 9, characterized in that: The fixing nut (4) is a hexagonal nut, and screwing the fixing nut (4) applies a downward force to the fixed upper plate (5).

11. A reactor irregular floor drain plugging device as claimed in claim 1, characterized in that: It is located above the floor drain bottom plate, on which a floor drain leakage hole (20) is processed, and the sealing rubber ring (18) contacts the floor drain bottom plate.

12. A reactor irregular floor drain plugging device as claimed in claim 1, characterized in that: It is located on the inner side of the floor drain side plate (22), and the inner surface of the floor drain side plate (22) is in contact with the sealing rubber ring (18) and the fixing rubber ring (7).

13. A reactor irregular floor drain plugging device as claimed in claim 12, characterized in that: A guide groove (21) is provided on the outer side thereof. The guide groove (21) is provided with a vertical plate and a horizontal plate. The vertical plate is in contact with the sealing rubber ring (18) and the fixing rubber ring (7), and the horizontal plate extends outward.

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