Device for restraining disturbance of steam generator tube bundle under modular construction condition
By placing a restraint in the ruptured heat transfer pipe and welding the plug at the pipe plate position, and combining the fixed connection between the flexible cable and the pipe plate, the wear problem of surrounding heat transfer pipe after the heat transfer pipe is solved, and the stability and safety of the steam generator tube bun is improved.
Patent Information
- Application Number
- CN202422227856.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-11
- Publication Date
- 2025-07-18
- Estimated Expiration
- 2034-09-11
AI Technical Summary
In a pressurized water reactor nuclear power plant, after the heat transfer pipe is broken, it is difficult for the prior art to effectively isolate the primary and secondary fluids, resulting in the ruptured heat transfer pipe wear on the surrounding heat transfer pipe, and the reworking process of the inner liner of the heat transfer pipe is immature and the effect is not good.
The restraint device under modular construction conditions is adopted, including the first pipe plate welding plug, flexible cable and pull head. By placing the restraint body in the broken heat transfer pipe and using the pipe plate welding plug at the pipe plate position, the broken heat transfer pipe is welded and plugged, and the flexible cable and pipe plate are combined to fix the connection between the flexible cable and the pipe plate to avoid the impact of vibration of the flexible cable.
It effectively prevents disturbance and wear of the surrounding heat transfer pipe by the ruptured heat transfer pipe, realizes the disturbance of the heat transfer pipe bundle under modular construction conditions, and improves the stability and safety of the steam generator.
Smart Images
Figure CN223122028U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of steam generator installation in a pressurized water reactor nuclear power plant under modular construction conditions, and particularly relates to a device for suppressing disturbance of a steam generator tube bundle under modular construction conditions. Background Art
[0002] In a pressurized water reactor nuclear power plant, the steam generator with an inverted U-shaped heat transfer tube is the most common heat exchange device. It is necessary to maximize the total area of the heat transfer tube, reduce the volume of the heat exchanger, and improve the heat exchange efficiency. During the design, the heat transfer tube wall is generally thinned as much as possible, the hole bridge spacing of the heat transfer tube plate is reduced, and the flow rate between the secondary tube bundles is increased. During manufacturing, if the manufacturing process of the heat transfer tube is unreasonable, the tube threading process is not up to standard, the quality control of the heat transfer tube support and anti-vibration component installation is not strict, and there are quality defects such as pits on the heat transfer tube, it will cause hidden dangers to the rupture of the heat transfer tube after commissioning. After commissioning, in a long-term service environment, it is inevitable that there will be problems such as primary side stress corrosion, secondary side intergranular corrosion, micro-vibration wear, foreign body impact wear, and galvanic corrosion caused by the accumulation of tube sheet mud in the gap between the tube sheet and the support plate to form a small gap; as the commissioning time increases, some heat transfer tubes will rupture, which will not only cause the primary side fluid to enter the secondary side fluid. In some cases, the broken heat transfer tube continues to expand and deteriorate under the disturbance of secondary side fluid scouring, and in the case of flow-induced vibration, it will cause secondary damage such as wear to the surrounding heat transfer tubes.
[0003] At present, if the heat transfer tube of the steam generator of a pressurized water reactor is damaged, the most common repair method is to plug the tube on the tube sheet of the heat transfer tube. Usually, two methods, mechanical plugging and welding plugging, are used to effectively repair and isolate the primary and secondary fluids of the steam generator. However, in some cases, the broken heat transfer tube is still washed by the secondary fluid, and its rupture position will continue to expand. If timely measures are not taken, secondary hazards such as wear will be caused to the surrounding heat transfer tubes. Although in some cases, if the location of the heat transfer tube rupture defect is relatively regular and the rupture size is small, the heat transfer tube lining method can also be used for repair, but the immature operation process of the heat transfer tube lining and poor repair effect have led to the seldom use of the lining repair process. Utility Model Content
[0004] In view of the defects or shortcomings in the prior art, the utility model provides a device for suppressing the disturbance of the steam generator tube bundle under modular construction conditions. It can not only effectively repair and isolate the primary side fluid from the secondary side fluid by welding the tube sheet and welding the plug, but also solve the subsequent secondary damage of the broken heat transfer tube to the surrounding heat transfer tubes, thereby realizing the suppression of the disturbance of the inverted U-shaped steam generator heat transfer tube bundle under modular construction conditions.
[0005] To achieve the above object, the utility model adopts the following technical solutions:
[0006] In a first aspect, an embodiment of the utility model provides a device for suppressing the disturbance of the steam generator tube bundle under modular construction conditions, including a constraint body, the constraint body is placed inside the heat transfer tube, the constraint body includes a first tube sheet welding plug, a flexible cable and a towing head, one end of the flexible cable is connected to the first tube sheet welding plug, and the other end is connected to the towing head.
[0007] Further, the first tube sheet welding plug is welded and sealed with the tube sheet arranged at the end of the heat transfer tube.
[0008] Further, the towing head is of a cylindrical structure, the outer diameter of the towing head is smaller than the inner diameter of the heat transfer tube, a first socket is provided on the end face of one end of the towing head, and the axis of the first socket coincides with the axis of the towing head.
[0009] Further, a towing hole is provided at the end of the towing head away from the first socket, and the towing hole is used for threading a towing wire.
[0010] Further, the first tube sheet welding plug is of a frustum structure, and the cone top angle of the first tube sheet welding plug is less than 1.5°.
[0011] Further, the diameter of the small diameter end of the first tube sheet welding plug is smaller than the inner diameter of the heat transfer tube, and the diameter of its large diameter end is larger than the inner diameter of the heat transfer tube.
[0012] Further, a second socket is provided at the small diameter end of the first tube sheet welding plug, and the axis of the second socket coincides with the axis of the first tube sheet welding plug.
[0013] Further, both ends of the flexible cable are respectively inserted into the first socket and the second socket, and are fixedly connected by welding.
[0014] Further, a second tube sheet welding plug is also provided at the end of the heat transfer tube away from the first tube sheet welding plug, and the second tube sheet welding plug is welded and sealed with the tube sheet arranged at the end of the heat transfer tube.
[0015] Further, the towing head, the flexible cable, the first tube sheet welding plug and the second tube sheet welding plug are all made of nickel-based Inconel 690 alloy.
[0016] Compared with the prior art, the beneficial effects of the utility model are as follows:
[0017] 1. The utility model effectively prevents the damaged heat transfer tube from causing disturbance wear to the surrounding heat transfer tubes by placing a restraint body inside the cracked heat transfer tube and then welding a plug to the tube sheet at the tube sheet position to weld and block the damaged heat transfer tube.
[0018] 2. One end of the flexible cable is fixedly connected to the first tube sheet welding plug of the utility model, and the first tube sheet welding plug is welded and fixed on the tube sheet, thereby preventing the flexible cable from moving inside the heat transfer tube due to vibration and affecting the suppression effect. Brief Description of the Drawings
[0019] Figure 1 It is a diagram showing the positional relationship between the heat transfer tube and the restraint body in an embodiment of the utility model;
[0020] Figure 2 It is a structural diagram of the restraint body in an embodiment of the utility model;
[0021] Figure 3 It is a schematic diagram of the machining of the tube sheet hole during the process of welding and plugging the heat transfer tube to the tube sheet in an embodiment of the utility model;
[0022] Figure 4 It is a diagram showing the positional relationship between the tube sheet hole and the plug during the process of welding and plugging the heat transfer tube to the tube sheet in an embodiment of the utility model;
[0023] Figure 5 It is a schematic diagram of the machining of the plug during the process of welding and plugging the heat transfer tube to the tube sheet in an embodiment of the utility model;
[0024] Figure 6 It is a diagram showing the connection state between the tube sheet hole and the plug during the process of welding and plugging the heat transfer tube to the tube sheet in an embodiment of the utility model;
[0025] Among them, 1. First tube sheet welding plug; 2. Flexible cable; 3. Traction head; 4. Heat transfer tube; 5. First socket; 6. Traction hole; 7. Second socket; 8. Second tube sheet welding plug; 9. Tube sheet. Detailed Embodiment
[0026] The present utility model will be further described below in conjunction with the drawings and embodiments.
[0027] A typical embodiment of the present utility model is as Figure 1 and Figure 2 shown. The device for suppressing the disturbance of the steam generator tube bundle under modular construction conditions includes a first tube sheet welding plug 1, a flexible cable 2, and a traction head 3. One end of the flexible cable 2 is connected to the first tube sheet welding plug 1, and the other end is connected to the traction head 3.
[0028] Specifically, the traction head 3, the flexible cable 2, and the first tube sheet welding plug 1 are all made of nickel-based Inconel 690 alloy.
[0029] The traction head 3 is a cylindrical structure, the outer diameter of the traction head 3 is smaller than the inner diameter of the heat transfer tube 4, the length of the traction head 3 is three times the inner diameter of the heat transfer tube 4, a first socket hole 5 is provided on the end face of one end of the traction head 3, the axis of the first socket hole 5 coincides with the axis of the traction head 3, the depth of the first socket hole 5 is 1.5 times the inner diameter of the heat transfer tube 4, and a traction hole 6 is provided at one end of the traction head 3 away from the first socket hole 5 for passing the traction line, through which the traction head 3 and the flexible cable 2 are pulled from the mouth of the heat transfer tube 4 into the heat transfer tube 4.
[0030] The first tube sheet welding plug 1 is a truncated cone structure, the cone top angle of the first tube sheet welding plug 1 is less than 1.5°, the diameter of the small diameter end is smaller than the inner diameter of the heat transfer tube 4, and the diameter of the large diameter end is larger than the inner diameter of the heat transfer tube 4, so that the first tube sheet welding plug 1 can be placed at the tube mouth of the heat transfer tube 4 and block the tube mouth of the heat transfer tube 4. The small diameter end of the first tube sheet welding plug 1 is provided with a second socket hole 7, and the axis of the second socket hole 7 coincides with the axis of the first tube sheet welding plug 1.
[0031] The flexible cable 2 is formed by twisting multiple small-diameter strands, the length of the flexible cable 2 is smaller than the length of the heat transfer tube 4, and the outer diameter of the flexible cable 2 is smaller than the inner diameter of the heat transfer tube 4, so that the flexible cable 2 can be placed inside the heat transfer tube 4. The inner diameters of the first socket 5 and the second socket 7 are the same as the outer diameters of the flexible cable 2, and the two ends of the flexible cable 2 are respectively inserted into the first socket 5 and the second socket 7, and are fixedly connected by welding.
[0032] The end of the heat transfer tube 4 away from the first tube sheet welding plug 1 is also provided with a second tube sheet welding plug 8 , and the second tube sheet welding plug 8 is welded and sealed with the tube sheet 9 .
[0033] The first tube sheet welding plug 1 and the second tube sheet welding plug 8 are both made of nickel-based Inconel 690 alloy rods, and the first tube sheet welding plug 1 and the second tube sheet welding plug 8 are both welded to the tube sheet 9. Specifically, Figure 3 As shown, the tube sheet hole on the tube sheet 9 is machined, and a J-shaped groove is machined around the tube sheet hole, such as Figure 4 As shown in the figure, two truncated cone-shaped plugs are processed from nickel-based Inconel690 alloy rods. The diameter of one end of the plug is smaller than the diameter of the tube sheet hole, and the other end is larger than the diameter of the tube sheet hole. The small diameter end of the plug is inserted into the tube sheet hole that needs to be plugged, and a line is drawn at the position where the plug is flush with the surface of the tube sheet cladding layer, and then Figure 5 As shown, the plug is cut off at a position offset 2mm from the large diameter end at the line, a cylindrical thin-walled groove is opened at the end face of the large diameter end of the plug, and a socket hole is opened at one of the small diameter ends of the plug so that its inner diameter is consistent with the outer diameter of the flexible cable 2. Finally, as shown in FIG.Figure 6 As shown, weld the plug to the tube sheet hole.
[0034] By fixedly connecting one end of the flexible cable 2 to the first tube sheet welding plug 1, and welding and fixing the first tube sheet welding plug 1 on the tube sheet 9, the flexible cable 2 is prevented from moving within the heat transfer tube 4 due to vibration, thus affecting the suppression effect.
[0035] Working principle
[0036] During use, first determine the position of the heat transfer tube to be plugged, and process and clean the tube sheets at both ends of the heat transfer tube.
[0037] On the primary side of the tube sheet of the steam generator, determine the heat transfer tube arrangement identification to identify the position of the U-shaped heat transfer tubes to be plugged.
[0038] On the primary side of the heat transfer tube sheet of the steam generator, locate the center of the tube sheet hole, and machine an arc J-shaped groove with a depth of 2.0 mm and a radius of 3 mm, removing the weld between the heat transfer tube and the tube sheet, the end of the heat transfer tube, and the surfacing layer on the primary side of the tube sheet hole, but not damaging the backing layer of the surfacing layer on the primary side of the tube sheet hole.
[0039] Use a traction wire with a smaller diameter to connect to the traction hole at the end of the traction head, and draw the flexible cable through the tube sheet position of the ruptured heat transfer tube and place it inside the ruptured heat transfer tube.
[0040] After placing the restraint body inside the damaged heat transfer tube, remove the traction wire.
[0041] Weld and seal the first tube sheet welding plug on the restraint body to the tube sheet;
[0042] Weld and seal the second tube sheet welding plug at the tube sheet at the end of the ruptured heat transfer tube away from the first tube sheet welding plug;
[0043] Before the steam generator is put into operation, conduct a leak detection on the sealed welding position.
[0044] The above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. For those skilled in the art, the present utility model can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.
Claims
1. Device for suppressing disturbance of steam generator tube bundle under modular construction conditions, characterized in that It includes a restraint body which is placed inside a heat transfer tube. The restraint body includes a first tube sheet welding plug, a flexible cable, and a traction head. One end of the flexible cable is connected to the first tube sheet welding plug, and the other end is connected to the traction head.
2. The device for suppressing the disturbance of the steam generator tube bundle under modular construction conditions according to claim 1, wherein The first tube sheet welding plug is welded and sealed with the tube sheet provided at the end of the heat transfer tube.
3. The device for suppressing the disturbance of the steam generator tube bundle under modular construction conditions according to claim 1, characterized in that, The traction head is of a cylindrical structure. The outer diameter of the traction head is smaller than the inner diameter of the heat transfer tube. A first receiving hole is provided on the end face of one end of the traction head, and the axis of the first receiving hole coincides with the axis of the traction head.
4. The device for suppressing the disturbance of the steam generator tube bundle under modular construction conditions according to claim 3, wherein A traction hole is provided at the end of the traction head away from the first receiving hole, and the traction hole is used for threading a traction wire.
5. The device for suppressing the disturbance of the steam generator tube bundle under modular construction conditions according to claim 4, wherein The first tube sheet welding plug is of a frustum shape, and the cone apex angle of the first tube sheet welding plug is less than 1.5°.
6. The device for suppressing the disturbance of the steam generator tube bundle under modular construction conditions according to claim 5, characterized in that, The diameter of the small-diameter end of the first tube sheet welding plug is smaller than the inner diameter of the heat transfer tube, and the diameter of its large-diameter end is larger than the inner diameter of the heat transfer tube.
7. The device for suppressing the disturbance of the steam generator tube bundle under modular construction conditions according to claim 6, wherein A second receiving hole is provided at the small-diameter end of the first tube sheet welding plug, and the axis of the second receiving hole coincides with the axis of the first tube sheet welding plug.
8. The device for suppressing the disturbance of the steam generator tube bundle under modular construction conditions as claimed in claim 7, wherein, Both ends of the flexible cable are inserted into the first receiving hole and the second receiving hole respectively, and are fixedly connected by welding.
9. The device for suppressing the disturbance of the steam generator tube bundle under modular construction conditions according to claim 1, wherein A second tube sheet welding plug is further provided at the end of the heat transfer tube away from the first tube sheet welding plug, and the second tube sheet welding plug is welded and sealed with the tube sheet provided at the end of the heat transfer tube.
10. The device for suppressing the disturbance of the steam generator tube bundle under modular construction conditions according to claim 1, wherein The traction head, the flexible cable, the first tube sheet welding plug, and the second tube sheet welding plug are all made of nickel-based Inconel690 alloy.