Steam generator secondary side feed water ring with foreign matter interception function

Abstract

This invention discloses a secondary-side feedwater ring for a steam generator with foreign object interception functionality. The feedwater ring includes a ring pipe and a J-shaped pipe mounted on the ring pipe, including a sleeve installed on the J-shaped pipe; and a nozzle installed at the bottom of the sleeve. One side of the nozzle has a filter hole for intercepting foreign objects, and the filter hole is located on the side of the nozzle facing the central region of the steam generator to avoid thermal shock to the secondary-side cylinder of the steam generator. This invention can add foreign object interception functionality to the feedwater ring of steam generators in in-service nuclear power plants, effectively preventing damage to heat transfer tubes from large-sized hazardous foreign objects and improving nuclear safety. The design of the filter hole direction and arrangement avoids unacceptable effects such as thermal shock and excessive resistance on in-service steam generators, and has a good foreign object interception effect.

Description

Technical Field

[0001] This invention relates to the field of nuclear power steam generator technology, and in particular to a secondary feedwater ring for a steam generator with foreign object interception function. Background Technology

[0002] As a crucial heat exchange device in pressurized water reactor nuclear power plants, the steam generator transfers heat from the primary coolant to the secondary feedwater, producing saturated steam to supply the secondary power unit. After entering the feedwater inlet pipe, the steam generator reaches the T-joint and splits into left and right directions to enter the feedwater ring. It then flows into the secondary side of the steam generator through the J-tubes on both sides.

[0003] Related technology 1: The inner diameter of the inverted J-shaped tube of the steam generator feedwater ring of the CPR1000 unit is about 52.5mm. The current structure does not have the ability to intercept foreign objects, which poses a risk that foreign objects may enter the steam generator tube bundle area and damage the heat transfer tubes, thus affecting nuclear safety.

[0004] Related Technology 2: The existing feedwater ring structure design of new steam generators with foreign object interception function is completed during the equipment design and manufacturing stage; the feedwater ring of the new steam generator is significantly different from the original design structure and thermal performance of the CPR1000 unit steam generator, and is not suitable for application in the CPR1000 in-service units.

[0005] Related Technology 3: Currently, the existing structure for adding a foreign object blocking device to the feedwater ring of the CPR1000 unit uses a compression deformation method to install and fix the device to the J-shaped pipe. However, the large wall thickness of both makes deformation difficult, resulting in installation challenges. Furthermore, this fixing method is unreliable; the turbulent flow within the feedwater ring can easily induce vibrations, posing a risk of loosening. The openings around the nozzle structure can cause thermal shock to the steam generator cylinder from the feedwater, unacceptably impacting the pressure boundary. The openings at the bottom of the nozzle structure allow long, thin foreign objects to pass through the foreign object blocking device more easily, reducing its interception effectiveness. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a steam generator secondary side feedwater ring that can be installed in a confined space without causing thermal shock fatigue to the secondary side cylinder of the steam generator, and also has the function of intercepting foreign objects.

[0007] The technical solution adopted by this invention to solve its technical problem is: a secondary side feedwater ring for a steam generator with foreign object interception function, the feedwater ring including a ring pipe and a J-shaped pipe installed on the ring pipe, comprising:

[0008] A sleeve, which is installed onto the J-shaped tube;

[0009] The nozzle is installed at the bottom of the sleeve. A filter hole for intercepting foreign objects is opened on one side of the nozzle, and the filter hole is opened on the side of the nozzle facing the central area of ​​the steam generator to avoid thermal shock to the secondary side cylinder of the steam generator.

[0010] Furthermore, in the secondary side feedwater ring of the steam generator with foreign object interception function, the sleeve preferably includes an arc-shaped section pipe and a straight section pipe, one end of which is fitted onto a J-shaped pipe;

[0011] The straight section tube is fixedly or detachably installed at the other end of the arc section tube, or the arc section tube and the straight section tube are an integral structure;

[0012] At least one plug weld hole is provided on the side of the arc segment tube away from the central area of ​​the steam generator, and the arc segment tube is welded or bonded to the J-shaped tube through the plug weld hole.

[0013] Furthermore, in the secondary side water supply ring of the steam generator with foreign object interception function, the nozzle is preferably screwed to the end of the straight section pipe, and the connection between the nozzle and the straight section pipe is strengthened by welding or bonding.

[0014] Furthermore, in the secondary side water supply ring of the steam generator with foreign object interception function, the diameter of the filter hole is preferably 6cm-8cm.

[0015] Furthermore, in the secondary side feedwater ring of the steam generator with foreign object interception function, preferably multiple filter holes are provided, and the total area of ​​the multiple filter holes is larger than the cross-section of the J-shaped pipe.

[0016] Furthermore, in the secondary side water supply ring of the steam generator with foreign object interception function, the total area of ​​the plurality of filter holes is preferably greater than or equal to 1.5 times the cross-section of the J-shaped tube.

[0017] Furthermore, in the secondary side feedwater ring of the steam generator with foreign object interception function, the feedwater ring preferably also includes a fixing mechanism for fixing the sleeve.

[0018] Furthermore, in the secondary side feedwater ring of the steam generator with foreign object interception function, the fixing mechanism preferably includes a clamp, a connector, an arc-shaped buckle, and an adjustment component;

[0019] The clamp is fitted onto the ring tube, the connector is installed on one side of the clamp, the arc-shaped buckle is installed on one side of the connector, and the arc-shaped buckle covers one side of the J-shaped tube. The arc-shaped buckle is connected to the sleeve through the adjustment component to adjust the tolerance between the sleeve and different J-shaped tubes.

[0020] Furthermore, in the secondary side feedwater ring of the steam generator with foreign object interception function, the adjusting component preferably includes an arc-shaped adjusting element and a fixing element;

[0021] The two ends of the arc-shaped adjusting member are respectively adjustablely mounted on the arc-shaped buckle and the sleeve via the fixing member.

[0022] Furthermore, in the secondary side water supply ring of the steam generator with foreign object interception function, a groove is preferably provided at the connection between the top of the nozzle and the straight section pipe, and the connection between the nozzle and the straight section pipe is increased by welding or bonding in the groove.

[0023] Implementing this invention has the following beneficial effects: it can add a foreign object interception function to the feedwater ring of the steam generator in an in-service nuclear power plant, effectively intercepting large-sized hazardous foreign objects from damaging the heat transfer tubes and improving nuclear safety. The design of the filter hole direction and arrangement will not cause unacceptable effects such as thermal shock or excessive resistance to the in-service steam generator, and has a good foreign object interception effect.

[0024] This invention is detachable, enabling installation in the confined space of the secondary side of the steam generator and inspection and removal of foreign objects during overhauls. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0026] Figure 1 This is a first-view structural schematic diagram of the secondary side feedwater ring of the steam generator with foreign object interception function according to the present invention.

[0027] Figure 2 This is a schematic diagram of the sleeve and nozzle of the first embodiment of the steam generator secondary side feedwater ring with foreign object interception function according to the present invention;

[0028] Figure 3 This is the first embodiment of the secondary feedwater ring of the steam generator with foreign object interception function according to the present invention. Figure 2 A schematic diagram of the cross-sectional structure;

[0029] Figure 4 This is a schematic diagram of the fixing mechanism of the first embodiment of the steam generator secondary side feedwater ring with foreign object interception function according to the present invention.

[0030] Explanation of the labels in the diagram:

[0031] 1. Ring pipe; 2. J-type pipe; 3. Sleeve; 4. Nozzle; 5. Filter hole; 6. Arc-shaped pipe section; 7. Straight pipe section; 8. Plug weld hole; 9. Clamp; 10. Connector; 11. Arc-shaped buckle shell; 12. Arc-shaped adjusting component; 13. Fixing component. Detailed Implementation

[0032] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or element referred to must have a specific orientation; therefore, they should not be construed as limitations on this invention.

[0033] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. The terms "first," "second," "third," etc., are only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0034] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, and circuits are omitted so as not to obscure the description of the invention with unnecessary detail.

[0035] Example 1: The technical solution adopted by the present invention to solve its technical problem is: by Figures 1 to 4 This invention discloses a secondary-side feedwater ring for a steam generator with foreign object interception function. The feedwater ring includes a ring pipe 1 and a J-shaped pipe 2 installed on the ring pipe 1, comprising:

[0036] Sleeve 3 is installed onto J-type tube 2;

[0037] Nozzle 4 is installed at the bottom of sleeve 3. A filter hole 5 for intercepting foreign objects is opened on one side of nozzle 4, and the filter hole 5 is opened on the side of nozzle 4 facing the central area of ​​steam generator to avoid thermal shock to the secondary side cylinder of steam generator.

[0038] Preferably, by designing the opening direction of the filter hole 5 so that the water flow direction is towards the central area of ​​the steam generator, the thermal shock problem of the secondary side cylinder of the steam generator can be avoided.

[0039] Alternatively, the nozzle 4 can be designed without openings at the bottom, which effectively intercepts long, thin foreign objects.

[0040] Specifically, to reduce the risk of large foreign objects damaging the heat transfer tubes of the steam generator from the source, the overall solution proposes to innovate the structural design of the J-type pipe 2 of the steam generator feedwater ring, adding a foreign object interception function to effectively intercept large metal foreign objects. The foreign object interception function is achieved through the structure of the sleeve 3 and the nozzle 4 with multiple filter holes 5. The porous structure of the nozzle 4 is used to prevent foreign objects in the feedwater from entering the secondary side of the steam generator, ensuring the stability of unit operation while also achieving the effect of intercepting foreign objects.

[0041] In addition, the nozzle 4 adopts a single-sided filter hole 5 structure, that is, the opening direction is towards the center area of ​​the steam generator, which can avoid considering the thermal shock generated on the secondary side cylinder of the steam generator when the feed water temperature is low.

[0042] Depend on Figures 2 to 3 As shown, the sleeve 3 includes an arc-shaped section of pipe 6 and a straight section of pipe 7, one end of which is fitted onto the J-shaped pipe 2;

[0043] The straight section pipe 7 is fixedly or detachably installed at the other end of the arc section pipe 6, or the arc section pipe 6 and the straight section pipe 7 are an integral structure; the arc section pipe 6 has at least one plug weld hole 8 on the side away from the central area of ​​the steam generator, and the arc section pipe 6 is welded or bonded to the J-type pipe 2 through the plug weld hole 8.

[0044] Preferably, the inner diameter of the sleeve 3 is slightly larger than the outer diameter of the J-shaped tube 2, the arc segment tube 6 is fitted onto the bottom of the J-shaped tube 2, the straight segment tube 7 is vertical and has no curvature, and the arc segment tube 6 has a certain curvature, which makes it easy to fit onto the J-shaped tube 2, and the curvature of the arc segment tube 6 is the same as the curvature of the J-shaped tube 2.

[0045] Alternatively, the upper curved section of the sleeve 3 may have an opening (plug weld hole 8), which is then plug welded to the inverted J-shaped pipe 2 of the water supply ring. Considering the dense arrangement of the inverted J-shaped pipes 2 and the limited surrounding working space, the plug weld design of the opening at the upper part of the sleeve 3 allows for adjustment of the direction of the plug weld hole 8 according to the on-site working space, facilitating on-site installation. This ensures that even if the plug weld fixing position of the sleeve 3 becomes loose, the nozzle 4 will self-lock with the water supply ring and will not fall off.

[0046] The nozzle 4 is screwed to the end of the straight section pipe 7, and the connection between the nozzle 4 and the straight section pipe 7 is strengthened by welding or bonding.

[0047] Preferably, the outer surface of the straight section pipe 7 is machined with external threads, and the inner wall of the nozzle 4 is machined with corresponding internal threads. The nozzle 4 is threadedly installed on the straight section pipe 7.

[0048] A groove 14 is provided at the connection between the top of the nozzle 4 and the straight section pipe 7. The connection between the nozzle 4 and the straight section pipe 7 is increased by welding or bonding within the groove 14.

[0049] Alternatively, after the nozzle 4 is connected to the straight section pipe 7 by a tool thread, spot welding is added for fixation. When it is necessary to remove foreign objects from inside the nozzle 4, the spot welding position is ground and the nozzle 4 can be unscrewed. After the foreign objects are cleaned, the nozzle 4 is reinstalled.

[0050] The groove 14 is partly formed on the straight section pipe 7 and partly formed on the inner top wall of the nozzle 4.

[0051] Specifically, the nozzle 4 structure is designed to be detachable, allowing for the inspection and removal of any foreign objects trapped inside during major overhauls.

[0052] The diameter of filter hole 5 is 6cm-8cm.

[0053] Preferably, based on the analysis of experience data on foreign object damage on the secondary side of the steam generator, it is determined that the diameter of the filter hole 5 of the nozzle 4 is about 7mm, which can effectively intercept metal foreign objects that are highly harmful to the heat transfer tubes of the steam generator, effectively reducing the risk of foreign objects getting stuck in the tube bundle area (tube bundle spacing 8mm) and causing continuous wear to the heat transfer tubes.

[0054] Specifically, the water supplied through the water ring goes to the tube bundle area below, where the tube bundle is used for heat exchange. The purpose of filter hole 5 is to prevent large foreign objects from reaching the tube bundle area through the water ring and causing damage to the tube bundle.

[0055] Multiple filter holes 5 are provided, and the total area of ​​the multiple filter holes 5 is greater than the cross-section of the J-shaped tube 2.

[0056] The total area of ​​the multiple filter holes 5 is greater than or equal to 1.5 times the cross-sectional area of ​​the J-shaped tube 2.

[0057] Preferably, the number and arrangement of the filter holes 5 on the nozzle 4 are designed to reduce the resistance, which does not exceed 1 bar under operating conditions, and ensures that the average water flow velocity is less than that of the original J-type pipe 2 structure, so as not to significantly affect the normal water supply of the steam generator.

[0058] Example 2, by Figure 1 and Figure 4The water supply ring also includes a fixing mechanism for fixing the sleeve 3.

[0059] The fixing mechanism includes a clamp 9, a connector 10, an arc-shaped buckle 11, and an adjustment assembly;

[0060] The clamp 9 is fitted onto the ring pipe 1, the connector 10 is installed on one side of the clamp 9, the arc-shaped buckle 11 is installed on one side of the connector 10, and the arc-shaped buckle 11 covers one side of the J-shaped pipe 2. The arc-shaped buckle 11 is connected to the sleeve 3 through the adjustment component to adjust the tolerance between the sleeve 3 and different J-shaped pipes 2.

[0061] Preferably, the clamp 9 is installed on the ring pipe 1 of the water supply ring, one end of the connector 10 is fixed to the clamp 9 by bolts, the arc-shaped buckle 11 is fixed to the other end of the connector 10, and the arc-shaped buckle 11 is fastened to the outer surface of the J-shaped pipe 2.

[0062] The adjustment assembly includes an arc-shaped adjustment component 12 and a fixing component 13; the two ends of the arc-shaped adjustment component 12 are respectively adjustablely mounted on the arc-shaped buckle shell 11 and the sleeve 3 through the fixing component 13.

[0063] Preferably, the arc-shaped adjusting member 12 has straight slots at both ends. The top of the arc-shaped buckle shell 11 and the top of the sleeve 3 are fixed to both ends of the arc-shaped adjusting member 13 by the fixing member 13. The fixing member 13 is installed in the straight slot and can be adjusted in position within the straight slot to shorten the distance between the arc-shaped buckle shell 11 and the sleeve 3. In other words, the height of the sleeve 3 installed on the J-shaped tube 2 can be adjusted. Different J-shaped tubes have different manufacturing tolerances, and adjustments are made during installation.

[0064] The beneficial effects obtained from the sleeve 3, nozzle 4, and filter hole 5 are as follows: This invention can add a foreign object interception function to the feedwater ring of the steam generator in an in-service nuclear power plant, effectively intercepting large-sized dangerous foreign objects from damaging the heat transfer tubes and improving nuclear safety. The design of the direction and arrangement of the filter hole 5 will not cause unacceptable effects such as thermal shock or excessive resistance to the in-service steam generator, and has a good foreign object interception effect.

[0065] This invention is detachable, enabling installation in the confined space of the secondary side of the steam generator and inspection and removal of foreign objects during overhauls.

[0066] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A secondary feedwater ring for a steam generator with foreign object interception function, the feedwater ring comprising a ring pipe (1) and a J-shaped pipe (2) mounted on the ring pipe (1), characterized in that, include: Sleeve (3), the sleeve (3) is installed on the J-shaped tube (2); Nozzle (4), the nozzle (4) is installed at the bottom of the sleeve (3), and a filter hole (5) for intercepting foreign objects is provided on one side of the nozzle (4), and the filter hole (5) is opened on the side of the nozzle (4) facing the central area of ​​the steam generator, so as to avoid thermal shock to the secondary side cylinder of the steam generator. The water supply ring also includes a fixing mechanism for fixing the sleeve (3), the fixing mechanism including a clamp (9), a connector (10), an arc-shaped buckle (11), and an adjustment component; The clamp (9) is fitted onto the ring tube (1), the connector (10) is installed on one side of the clamp (9), the arc-shaped buckle (11) is installed on one side of the connector (10), and the arc-shaped buckle (11) covers one side of the J-shaped tube (2). The arc-shaped buckle (11) is connected to the sleeve (3) through the adjustment component to adjust the tolerance between the sleeve (3) and different J-shaped tubes (2).

2. The secondary feedwater ring of the steam generator with foreign object interception function according to claim 1, characterized in that, The sleeve (3) includes an arc-shaped section (6) and a straight section (7) that fit one end of the J-shaped tube (2). The straight section pipe (7) is fixedly or detachably installed at the other end of the arc section pipe (6), or the arc section pipe (6) and the straight section pipe (7) are an integral structure; The arc segment pipe (6) has at least one plug weld hole (8) on the side away from the central area of ​​the steam generator. The arc segment pipe (6) is welded or bonded to the J-shaped pipe (2) through the plug weld hole (8).

3. The secondary feedwater ring of the steam generator with foreign object interception function according to claim 2, characterized in that, The nozzle (4) is screwed to the end of the straight section pipe (7).

4. The secondary feedwater ring of the steam generator with foreign object interception function according to claim 1, characterized in that, The diameter of the filter hole (5) is 6cm-8cm.

5. The secondary feedwater ring of the steam generator with foreign object interception function according to claim 1, characterized in that, The filter hole (5) has multiple openings, and the total area of ​​the multiple filter holes (5) is greater than the cross-section of the J-shaped tube (2).

6. The secondary feedwater ring of the steam generator with foreign object interception function according to claim 5, characterized in that, The total area of ​​the plurality of filter holes (5) is greater than or equal to 1.5 times the cross-section of the J-shaped tube (2).

7. The secondary feedwater ring of a steam generator with foreign object interception function according to claim 1, characterized in that, The adjustment assembly includes an arc-shaped adjustment component (12) and a fixing component (13); The two ends of the arc-shaped adjusting member (12) are respectively adjustablely mounted on the arc-shaped buckle shell (11) and the sleeve (3) through the fixing member (13).

8. The secondary feedwater ring of the steam generator with foreign object interception function according to claim 2, characterized in that, A groove (14) is provided at the connection between the top of the nozzle (4) and the straight section pipe (7). The connection between the nozzle (4) and the straight section pipe (7) is increased by welding or bonding in the groove (14).

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