External sacrificial anode protection device for secondary filter screen of nuclear power station condenser

Abstract

The invention particularly relates to an external sacrificial anode protection device for a secondary filter screen of a nuclear power station condenser. The external sacrificial anode protection device comprises a blind flange, a pipe barrel flange, a special-shaped rod-shaped anode block, a pipe barrel welding plug, a pre-protection filter screen and a corrosion-resistant alloy mesh cage anode pipe barrel, the upper end of the corrosion-resistant alloy mesh cage anode pipe barrel is welded with a pipe barrel flange, and the lower end is welded with a pipe barrel welding plug; the pipe barrel flange and the blind plate flange are fastened and hermetically connected; the center of the blind flange is in threaded connection with a special-shaped rod-shaped anode block; mesh cage type orifices are uniformly formed in the barrel body of the corrosion-resistant alloy mesh cage anode pipe barrel in the radial direction; an anti-corrosion layer is arranged in the pre-protection filter screen, a fillet weld is arranged between the anti-corrosion alloy mesh cage anode pipe barrel and the outer pipe wall of the pre-protection filter screen, and a surfacing layer is arranged between the anti-corrosion alloy mesh cage anode pipe barrel and an opening in the pre-protection filter screen. The anode block can be directly disassembled and assembled outside the filter screen, the anode block is convenient to replace, the construction safety risk of personnel is reduced, the filter screen is complete and reliable, and safe operation of the nuclear power station is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of protection of secondary filter screens of condensers in nuclear power plants, and in particular to an external sacrificial anode protection device for secondary filter screens of condensers in nuclear power plants. Background Art

[0002] The cooling water system of nuclear power plant equipment is the final heat sink of nuclear-grade equipment. The secondary filter of nuclear power plant condenser is an important part of the cooling water system of nuclear power plant equipment. Its pipe diameter is generally greater than DN1000mm, the material is austenitic stainless steel, the anti-corrosion type is anodic protection, and the conveying fluid medium is seawater. When the filter material comes into contact with seawater, there is a certain potential difference between the various parts of the filter material surface, which is very prone to electrochemical corrosion, posing a great hidden danger to the safe and reliable operation of the equipment.

[0003] In order to extend the service life of the filter and its accessories in seawater, the electrochemical corrosion is slowed down by installing anode blocks. At present, the anode blocks are installed by fixing them with brackets inside the filter. When replacing the anode blocks in this installation method, it is necessary to open a manhole on the filter or remove the valve to allow personnel to enter the filter for operation. The construction space is closed, and there are industrial safety risks such as flooding, lack of oxygen, and poor construction environment.

[0004] During the long-term operation of nuclear power plants, due to adverse factors such as seawater scouring and support corrosion, it is common for the built-in fixed support anode blocks to consume volume and break, and the anode block fragments to fall off inside the filter, damaging the filter. In severe cases, this can cause damage to the downstream condenser, threatening the safe operation of the nuclear power plant. Summary of the invention

[0005] Based on this, it is necessary to provide an external sacrificial anode protection device for the secondary filter of the condenser of a nuclear power plant, which can directly disassemble and install the anode blocks on the outside of the filter, facilitate the replacement of the anode blocks, reduce the safety risks of personnel in construction, ensure the integrity and reliability of the filter, and ensure the safe operation of the nuclear power plant.

[0006] In order to solve the above problems, the present invention provides the following technical solutions:

[0007] A nuclear power plant condenser secondary filter external sacrificial anode protection device, comprising a blind flange, a tube flange, a special-shaped rod-shaped anode block, a tube welding plug, a pre-protection filter and a corrosion-resistant alloy mesh cage anode tube;

[0008] The upper end of the corrosion-resistant alloy mesh anode tube is welded to the tube flange, and the lower end of the corrosion-resistant alloy mesh anode tube is welded to the tube welding plug; the tube flange is fastened and sealed to the blind flange; the center of the blind flange is threaded to connect the special-shaped rod-shaped anode block;

[0009] The body of the corrosion-resistant alloy mesh cage anode tube is evenly provided with mesh cage-type holes in radial direction; an anti-corrosion layer is provided inside the pre-protection filter, a fillet weld is provided between the corrosion-resistant alloy mesh cage anode tube and the outer tube wall of the pre-protection filter, and a surfacing layer is provided between the corrosion-resistant alloy mesh cage anode tube and the inner opening of the pre-protection filter.

[0010] As one of the feasible methods, the material of the blind flange is consistent with the corrosion-resistant alloy mesh anode tube, and the specification is selected according to the DN100mm blind flange in ASME 16.5;

[0011] The material of the tube flange is the same as that of the corrosion-resistant alloy mesh anode tube, and the specification is selected according to the DN100mm loose flange in ASME 16.5;

[0012] The material of the welding plug is consistent with that of the corrosion-resistant alloy mesh cage anode tube, and the specifications are selected according to the matching corrosion-resistant alloy mesh cage anode tube welding plug;

[0013] The corrosion-resistant alloy mesh anode tube is a pipe with a diameter of DN100mm and a wall thickness of ≥3.91mm. The material is nickel-based corrosion-resistant alloy ASME B167 NO.8367. The specifications are selected according to the pipe with a nominal outer diameter of DN100mm and a wall thickness of SCH40S in ASME 31.1.

[0014] As one of the feasible ways, the tube flange and the blind plate flange are fastened and connected by fasteners, and the fasteners include bolts and nuts; a sealing gasket is provided between the tube flange and the blind plate flange, and the tube flange and the blind plate flange are sealed and connected by the sealing gasket, and the sealing gasket is an expanded polytetrafluoroethylene gasket.

[0015] In this embodiment, as one of the achievable methods, the aperture of the mesh cage type orifice decreases along the center direction of the forecast protection filter screen, and the aperture of the mesh cage type orifice includes 16mm, 12mm, 8mm and 4mm;

[0016] The vertical spacing between mesh cage type holes is ≤50mm, the horizontal spacing between mesh cage type holes is ≤20mm, the distance between the upper part of the mesh cage type holes and the inner wall of the pre-protection filter is h1≥100mm, and the distance between the lower part of the mesh cage type holes and the weld of the pipe welding plug is h2≥200mm.

[0017] As one of the feasible ways, the weld leg height of the fillet weld is ≥4mm; the fillet weld is welded by welding wire with grade ERNCrMo-3 and is subjected to liquid penetration inspection after welding.

[0018] As one of the feasible ways, the length h3 of the cladding layer is ≥10 mm, and the height B is ≥3 mm; the cladding layer is welded by welding wire with a grade of ERNCrMo-3, and is subjected to liquid penetration inspection after welding.

[0019] As one achievable manner, the special-shaped rod-shaped anode block comprises a rod-shaped anode block and special-shaped protrusions evenly arranged radially on the outer surface of the rod-shaped anode block; the diameter of the special-shaped rod-shaped anode block is D=90 mm; and the length of the special-shaped protrusions is L=15 mm.

[0020] As one of the feasible ways, an anode fixing stud is welded at the center of the blind flange. The anode fixing stud is an external threaded stud with a diameter of 16 mm. An internal threaded hole is provided at the center of the special-shaped rod-shaped anode block. The size of the internal threaded hole is consistent with that of the anode fixing stud. The anode fixing stud is threadedly connected to the internal threaded hole.

[0021] As one of the feasible ways, a limit stop is provided on the blind flange, and the anode fixing stud and the special-shaped rod-shaped anode block are threadedly connected to the limit stop; the limit stop is made of rubber, with a thickness of ≥100mm and a plane size consistent with that of the special-shaped rod-shaped anode block.

[0022] As one of the feasible ways, the pre-protection filter is the nuclear power plant equipment cooling water system pipeline, made of low-carbon steel and with a size of DN1000mm; the anti-corrosion layer is the internal anti-corrosion layer of the nuclear power plant equipment cooling water system pipeline.

[0023] Beneficial technical effects of the present invention:

[0024] The external sacrificial anode protection device for the secondary filter of the condenser of a nuclear power plant of the present invention is fixed to the pre-protection filter by molten welding, and the device and the pre-protection filter can be separated by disassembling the blind flange of the cage tube, so that the anode block is easy to disassemble and replace, which is convenient for the staff to operate, improves the work efficiency, and reduces the safety risk of personnel in construction; the cage tube structure prevents the anode block from falling off and entering the downstream condenser secondary filter during long-term operation of the nuclear power plant, causing damage to the condenser secondary filter, maintains the integrity and reliability of the condenser secondary filter, and reduces the operation risk of the condenser secondary filter; the device material is made of nickel-based corrosion-resistant alloy, which makes the device zero-corrosion in the seawater environment, and solves the corrosion and aging problem of the device under long-term operation of the nuclear power plant; the internal welding layer of the pipeline protects the pipeline at the opening, which simplifies the construction difficulty of the pipeline anti-corrosion layer; the surface area of ​​the special-shaped rod-shaped anode block is larger under the same volume, and the sacrificial anode effect is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of an embodiment of a nuclear power plant condenser secondary filter external sacrificial anode protection device of the present invention;

[0026] Figure 2 It is a schematic diagram of the connection between a blind flange and a special-shaped rod-shaped anode block according to an embodiment;

[0027] Figure 3 The figure is a schematic structural view of an embodiment of a special-shaped rod-shaped anode block.

[0028] In the figure, 1. blind flange; 2. sealing gasket; 3. tube flange; 4. fasteners; 5. anode fixing studs; 6. special-shaped rod-shaped anode blocks; 7. limit stops; 8. tube welding plugs; 9. pre-protection filter; 10. mesh cage type orifice; 11. fillet weld; 12. weld overlay; 13. anti-corrosion layer; 14. internal threaded hole; 15. corrosion-resistant alloy mesh cage anode tube. DETAILED DESCRIPTION

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0030] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0031] The technical solution of the present invention is clearly and completely described below in conjunction with the accompanying drawings and specific embodiments.

[0032] See also Figure 1-3 The present embodiment provides a nuclear power plant condenser secondary filter external sacrificial anode protection device, comprising a blind flange 1, a tube flange 3, a special-shaped rod-shaped anode block 6, a tube welding plug 8, a pre-protection filter 9 and a corrosion-resistant alloy mesh anode tube 15;

[0033] The upper end of the corrosion-resistant alloy mesh anode tube 15 is welded to the tube flange 3, and the lower end of the corrosion-resistant alloy mesh anode tube 15 is welded to the tube welding plug 8; the tube flange 3 is fastened and sealed to the blind flange 1; the center of the blind flange 1 is threadedly connected to the special-shaped rod-shaped anode block 6;

[0034] The corrosion-resistant alloy mesh cage anode tube 15 has mesh cage-type holes 10 evenly arranged in the radial direction of the tube body; an anti-corrosion layer 13 is arranged inside the pre-protection filter 9, a fillet weld 11 is arranged between the corrosion-resistant alloy mesh cage anode tube 15 and the outer tube wall of the pre-protection filter 9, and a surfacing layer 12 is arranged between the corrosion-resistant alloy mesh cage anode tube 15 and the internal opening of the pre-protection filter 9.

[0035] In order to protect the pre-protection filter screen 9 and simplify the construction process of the anti-corrosion layer 13 inside the pre-protection filter screen 9, a surfacing layer 12 is provided between the corrosion-resistant alloy mesh cage anode tube 15 and the inner tube wall of the pre-protection filter screen 9.

[0036] The corrosion-resistant alloy mesh cage anode tube 15 has mesh cage-type openings 10 arranged radially on its body, which facilitates the inflow and outflow of seawater into the corrosion-resistant alloy mesh cage anode tube 15 and effectively prevents the irregular rod-shaped anode blocks 6 from breaking and falling into the pre-protection filter 9 .

[0037] The special-shaped structure of the special-shaped rod-shaped anode block 6 increases the contact surface area between the anode and seawater, thereby promoting the anode protection effect.

[0038] In this embodiment, as one of the achievable methods, the material of the blind flange 1 is consistent with the corrosion-resistant alloy mesh anode tube 15, and the specification is selected according to the DN100mm blind flange in ASME 16.5;

[0039] The material of the tube flange 3 is consistent with that of the corrosion-resistant alloy mesh anode tube 15, and the specification is selected according to the DN100mm loose flange in ASME 16.5;

[0040] The material of the welding plug 8 is consistent with that of the corrosion-resistant alloy mesh cage anode tube 15, and the specifications are selected according to the matching welding plug of the corrosion-resistant alloy mesh cage anode tube 15;

[0041] The corrosion-resistant alloy mesh anode tube 15 is a pipe with a diameter of DN100mm and a wall thickness of ≥3.91mm, and is made of a nickel-based corrosion-resistant alloy ASME B167 NO.8367. The specification is selected according to the pipe with a nominal outer diameter of DN100mm and a wall thickness of SCH40S in ASME 31.1.

[0042] The device adopts nickel-based corrosion-resistant alloy, which makes the device zero-corrosion in seawater environment.

[0043] In this embodiment, as one of the feasible ways, the tube flange 3 and the blind flange 1 are fastened and connected by fasteners 4, and the fasteners 4 include bolts and nuts; a sealing gasket 2 is provided between the tube flange 3 and the blind flange 1, and the tube flange 3 and the blind flange 1 are sealed and connected by the sealing gasket 2, and the sealing gasket 2 is an expanded polytetrafluoroethylene gasket.

[0044] In this embodiment, as one of the achievable methods, the aperture of the mesh-cage-type orifice 10 decreases along the center direction of the forecast protection filter 9, and the aperture of the mesh-cage-type orifice 10 includes 16 mm, 12 mm, 8 mm and 4 mm;

[0045] The vertical spacing between the 10 mesh cage type holes is ≤50mm, the horizontal spacing between the 10 mesh cage type holes is ≤20mm, the distance h1 between the upper part of the mesh cage type holes 10 and the inner wall of the pre-protection filter 9 is ≥100mm, and the distance h2 between the lower part of the mesh cage type holes 10 and the weld of the pipe welding plug 8 is ≥200mm.

[0046] In this embodiment, as one of the achievable ways, the weld leg height of the fillet weld 11 is ≥4 mm; the fillet weld 11 is welded by welding wire with the grade of ERNCrMo-3, and is subjected to liquid penetration inspection after welding.

[0047] In this embodiment, as one of the feasible ways, the length h3 of the cladding layer 12 is ≥10 mm, and the height B is ≥3 mm; the cladding layer 12 is welded by welding wire with the grade of ERNCrMo-3, and is subjected to liquid penetration inspection after welding.

[0048] In this embodiment, as one of the achievable ways, the special-shaped rod-shaped anode block 6 comprises a rod-shaped anode block and special-shaped protrusions radially and uniformly arranged on the outer surface of the rod-shaped anode block; the diameter of the special-shaped rod-shaped anode block 6 is D=90 mm; and the length of the special-shaped protrusions is L=15 mm.

[0049] In this embodiment, as one of the feasible ways, an anode fixing stud 5 is welded at the center of the blind flange 1, and the anode fixing stud 5 is an external threaded stud with a diameter of 16 mm. An internal threaded hole 14 is provided at the center of the special-shaped rod-shaped anode block 6, and the size of the internal threaded hole 14 is consistent with that of the anode fixing stud 5. The anode fixing stud 5 is threadedly connected to the internal threaded hole 14.

[0050] In this embodiment, as one of the feasible ways, a limit stop 7 is provided on the blind flange 1, and the anode fixing stud 5 and the internal threaded hole 14 are connected to the limit stop 7; the limit stop 7 is made of rubber, with a thickness of ≥100mm, and the plane size is consistent with the special-shaped rod-shaped anode block 6.

[0051] In this embodiment, as one of the feasible methods, the pre-protection filter 9 is a pipeline of the cooling water system of nuclear power plant equipment, made of low-carbon steel and with a size of DN1000mm; the anti-corrosion layer 13 is an internal anti-corrosion layer of the pipeline of the cooling water system of nuclear power plant equipment.

[0052] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A nuclear power plant condenser secondary filter external sacrificial anode protection device, characterized in that: It comprises a blind flange (1), a tube flange (3), a special-shaped rod-shaped anode block (6), a tube welding plug (8), a pre-protection filter (9) and a corrosion-resistant alloy mesh cage anode tube (15); The upper end of the corrosion-resistant alloy mesh anode tube (15) is welded to a tube flange (3), and the lower end of the corrosion-resistant alloy mesh anode tube (15) is welded to a tube welding plug (7); the tube flange (3) is tightly and hermetically connected to the blind flange (1); the center of the blind flange (1) is threadedly connected to the special-shaped rod-shaped anode block (6); The body of the corrosion-resistant alloy mesh cage anode tube (15) is evenly provided with mesh cage-type openings (10) in the radial direction; an anti-corrosion layer (13) is provided inside the pre-protection filter (9); a fillet weld (11) is provided between the corrosion-resistant alloy mesh cage anode tube (15) and the outer tube wall of the pre-protection filter (9); and a cladding layer (12) is provided between the corrosion-resistant alloy mesh cage anode tube (15) and the inner opening of the pre-protection filter (9).

2. The nuclear power plant condenser secondary filter external sacrificial anode protection device according to claim 1, characterized in that: The materials of the blind flange (1), the tube flange (3) and the tube welding plug (8) are all consistent with the corrosion-resistant alloy mesh cage anode tube (15); the material of the corrosion-resistant alloy mesh cage anode tube (15) is nickel-based corrosion-resistant alloy.

3. The external sacrificial anode protection device for secondary filter screen of condenser in nuclear power plant according to claim 1, characterized in that: The aperture of the mesh-cage type orifice (10) decreases along the center direction of the pre-protection filter (9), and the apertures of the mesh-cage type orifice (10) include 16 mm, 12 mm, 8 mm and 4 mm; the vertical spacing between the mesh-cage type orifices (10) is ≤50 mm, the horizontal spacing between the mesh-cage type orifices (10) is ≤20 mm, the distance h1 between the upper part of the mesh-cage type orifice (10) and the inner wall of the pre-protection filter (9) is ≥100 mm, and the distance h2 between the lower part of the mesh-cage type orifice (10) and the weld of the pipe welding plug (8) is ≥200 mm.

4. The external sacrificial anode protection device for secondary filter screen of condenser in nuclear power plant according to claim 1, characterized in that: The weld leg height of the fillet weld (11) is ≥4 mm; the fillet weld (11) is welded by welding wire with the grade of ERNCrMo-3, and is subjected to liquid penetration inspection after welding.

5. The external sacrificial anode protection device for secondary filter screen of condenser in nuclear power plant according to claim 1, characterized in that: The length h3 of the cladding layer (12) is ≥10 mm, and the height B is ≥3 mm; the cladding layer (12) is welded by welding wire with the grade of ERNCrMo-3, and is subjected to liquid penetration inspection after welding.

6. The external sacrificial anode protection device for secondary filter screen of condenser in nuclear power plant according to claim 1, characterized in that: The special-shaped rod-shaped anode block (6) comprises a rod-shaped anode block and special-shaped protrusions evenly arranged radially on the outer surface of the rod-shaped anode block; the diameter of the special-shaped rod-shaped anode block (6) is D=90 mm; and the length of the special-shaped protrusions is L=15 mm.

7. The external sacrificial anode protection device for secondary filter screen of condenser in nuclear power plant according to claim 1, characterized in that: An anode fixing stud (5) is welded at the center of the blind flange (1), and an internal threaded hole (14) is provided at the center of the special-shaped rod-shaped anode block (6). The size of the internal threaded hole (14) is consistent with that of the anode fixing stud (5), and the anode fixing stud (5) is threadedly connected to the internal threaded hole (14).

8. The external sacrificial anode protection device for secondary filter screen of condenser in nuclear power plant according to claim 7, characterized in that: A limit stopper (7) is provided on the blind flange (1), and the anode fixing stud (5) and the internal threaded hole (14) are threadedly connected to the limit stopper (7); the limit stopper (7) is made of rubber, has a thickness of ≥100 mm, and has the same plane size as the special-shaped rod-shaped anode block (6).

9. According to the external sacrificial anode protection device for the secondary filter screen of the condenser of a nuclear power plant as described in claim 1, the tube flange (3) and the blind flange (1) are fastened and connected by fasteners (4), and the fasteners (4) include bolts and nuts; a sealing gasket (2) is provided between the tube flange (3) and the blind flange (1), and the tube flange (3) and the blind flange (1) are sealed and connected by the sealing gasket (2).

10. The external sacrificial anode protection device for secondary filter screen of condenser in nuclear power plant according to claim 1, characterized in that: The pre-protection filter (9) is a pipeline of a cooling water system of equipment in a nuclear power plant; and the anti-corrosion layer (13) is an internal anti-corrosion layer of the pipeline of a cooling water system of equipment in a nuclear power plant.

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