Pump sets for nuclear power plants

Abstract

The present invention relates to the technical field of nuclear power plant pumps and discloses a nuclear power plant pump group, which is mainly used in important plant water intake structures of AP1000 and CAP1400 nuclear power plants. The pump has a submerged length of 6 meters or more and comprises a pump assembly, a casing, a first mounting assembly, and a second mounting assembly. The first mounting assembly and the second mounting assembly are located at different mounting levels. The casing is mounted on the first mounting assembly, and the pump assembly is mounted on the second mounting assembly. The weight of the pump assembly and the weight of the casing are independently borne by the different mounting levels. The casing is provided so that the pump does not directly contact seawater flowing in the flow path of the important plant water intake structure of the nuclear power plant. The technical defects of existing pumps, such as high vibration and noise during operation, easy wear of motor bearings, swinging of the connection between the upper, middle and lower water pipes, and easy breakage of the upper water pipe and the upper shaft at the pump support, are completely solved. The operational safety and reliability of the nuclear power plant pump are improved, the service life of the pump is extended, and the operation and maintenance costs of the pump are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power plant pumps, in particular to a nuclear power plant pump group. Background Art

[0002] In AP1000 and CAP1400 nuclear power plants, the cooling method for nuclear power plant units is to use water pumps to pump seawater to cool the unit equipment and ensure safe and stable operation of the nuclear power units. These water pumps have a submerged length of 6 meters or more and operate in seawater, which contains sediment and marine organisms. The flow of seawater also creates numerous vortices, which can affect the pump's stability.

[0003] In existing nuclear power plant pump technology, the motor bears the weight of the pump rotor and axial force, resulting in high operating temperatures and easily damaged bearings. The upper water pipe is a non-reinforced structure connected to an elbow. The water thrust, seawater vortices, and lateral thrust generated during pump operation can cause multiple alternating fatigue at the upper water pipe and pump support, as well as at the connections between the middle water pipes. This can cause oscillation at the joints of the upper, middle, and lower water pipes, eccentric vibration of the center shaft, and wear on the guide bearings and center shaft. Furthermore, because the nuclear power plant's pumps are suspended vertically and lack external casing, they come into direct contact with the seawater flowing through the plant's critical water intake structure. This seawater flow generates multiple, irregular vortices, concentrating all the water thrust and vibration forces generated on the upper portion of the pump support's baseplate, as well as the water thrust, seawater vortex forces, lateral seawater flow thrust, and vibration forces generated on the lower portion of the baseplate. This causes multi-source fatigue fractures in the pump's riser pipe and upper shaft. Furthermore, the pumps are not equipped with, or are insufficiently equipped with, detection probes, making it impossible to monitor the pump's operation in real time and identify any problems. Consequently, the pump's safety and reliability are low, impacting the safe and stable operation of the nuclear power unit. Summary of the Invention

[0004] The purpose of the present invention is: the present invention provides a pump group for a nuclear power plant to solve the technical problem that the pumps for a nuclear power plant in the existing technology are in direct contact with the seawater flowing in the flow channel of the important plant water intake structure of the nuclear power plant, the flow of seawater generates multiple irregular vortices, and the water thrust and vibration force generated by the upper part of the bottom plate of all pump supports and the water thrust, seawater rising and falling vortex force, seawater flow lateral thrust, and vibration force generated by the lower part of the bottom plate of the pump support are all concentrated on the bottom plate of the pump support, causing multi-source fatigue fracture of the upper water pipe and upper shaft of the pump.

[0005] In order to achieve the above-mentioned object, the present invention provides a pump group for a nuclear power plant, comprising a pump assembly; the pump assembly comprises a motor, a motor base, a pump support, a thrust bearing assembly, a pump shaft, an upper water pipe, a middle water pipe, a lower water pipe, a water outlet horn, a guide vane, a pump cover and a filter screen; the motor is arranged on the motor base and connected to the pump shaft, and the motor base is arranged on the pump support; the thrust bearing assembly is connected to the pump support after passing through the pump shaft; the upper water pipe, the middle water pipe and the lower water pipe are sequentially connected to form a water pipe, the upper end of the upper water pipe is connected to the pump support, and the lower end of the lower water pipe is connected to the water outlet horn; the water outlet horn is connected to the guide vane, the guide vane is connected to the pump cover, and the pump cover is connected to the filter screen;

[0006] The invention also includes a casing, a first installation assembly and a second installation assembly; a pump well is preset in the primary soil layer;

[0007] The first mounting assembly is connected to the surface or inner wall of the primary soil layer, and the casing is mounted on the first mounting assembly;

[0008] An installation pit is preset at the edge of the wellhead of the pump well, and the second installation component is located at a predetermined position of the installation pit. A secondary soil layer is filled into the installation pit to fix the second installation component, so that the second installation component and the first installation component are located at different installation levels. After the pump assembly passes through the casing, it is installed on the second installation component through the pump support.

[0009] In some embodiments of the present application, the first mounting assembly includes a first mounting plate and a first bottom plate; the first mounting plate is placed on the surface of the primary soil layer, with its inner edge flush with the wellhead of the pump well and its outer edge located at a position corresponding to the mounting pit; the first bottom plate is located between the first mounting plate and the primary soil layer.

[0010] The second mounting assembly includes a second mounting plate and an anchor bolt; the lower end of the anchor bolt is located in the mounting groove, and the upper end thereof passes through the first mounting plate and is connected to the second mounting plate, so that the second mounting plate is at a predetermined height relative to the first mounting plate, and the inner edge of the second mounting plate is horizontally spaced a predetermined distance from the inner edge of the first mounting plate;

[0011] A secondary soil layer is filled into the installation pit to simultaneously fix the first mounting plate, the second mounting plate and the anchor bolts, and the inner edge of the secondary soil layer is flush with the inner edge of the second mounting plate to form a secondary wellhead. The casing is installed on the first mounting plate after passing through the secondary wellhead and the wellhead, and the pump support is installed on the second mounting plate.

[0012] In some embodiments of the present application, the first mounting assembly includes a first mounting plate, a side mounting plate, a first mounting rib, and a second mounting rib; two side mounting plates are provided at a predetermined height on the inner wall of the pump well located above the high liquid level; the first mounting rib is horizontally provided on one of the side mounting plates, and the two ends of the second mounting rib are respectively connected to the other side mounting plate and the first mounting rib, and the second mounting rib forms an angle of 15°-60° with the first mounting rib; the first mounting plate is provided on the first mounting rib, and its inner edge is flush with the end of the first mounting rib; and at least three groups of the first mounting rib and the second mounting rib are provided at equal intervals along the inner wall of the pump well; the casing is installed on the first mounting plate after passing through the wellhead;

[0013] The second mounting assembly includes a second mounting plate and an anchor bolt; the lower end of the anchor bolt is located in the mounting pit, and the upper end thereof is connected to the second mounting plate, so that the second mounting plate is located on the surface of the primary soil layer, and the mounting pit is filled with a secondary soil layer to fix the second mounting plate and the anchor bolt, and the pump support is installed on the second mounting plate.

[0014] In some embodiments of the present application, the bottom end of the casing is a closed structure, the bottom end of the filter screen is at a predetermined height from the bottom end of the casing, and the lower end of the casing is provided with filter holes spaced circumferentially.

[0015] In some embodiments of the present application, the filter holes are strip-shaped filter holes.

[0016] In some embodiments of the present application, the bottom end of the casing is an open structure, a hose is provided between the pump cover and the filter screen, and the bottom end of the casing is flush with the contact surface of the hose and the filter screen.

[0017] In some embodiments of the present application, the outer wall of the upper water pipe is provided with reinforcing ribs along the axial direction.

[0018] In some embodiments of the present application, a first side plate and a first support rib are further provided; the first side plate is provided on the inner wall of the pump well, and the first support rib is horizontally provided between the first side plate and the outer wall of the casing; and at least three groups of the first side plates and the first support rib are provided at equal intervals along the inner wall of the pump well.

[0019] In some embodiments of the present application, a second side plate and a second support rib are further provided; the second side plate is provided on the inner wall of the pump well, the second support rib is provided between the second side plate and the outer wall of the casing, and forms an angle of 12°-75° with the horizontal plane, and the second support rib is located at the corresponding position of the guide vane; at least three groups of the second side plates and the second support rib are provided at equal intervals along the inner wall of the pump well.

[0020] In some embodiments of the present application, the pump assembly is provided with a plurality of temperature probes, vibration probes and pressure probes;

[0021] A shaft seal is provided in the pump support, a cooling coil is provided in the thrust bearing assembly, and a cooling pipe is provided to connect the cooling coil and the shaft seal, and the cooling pipe is provided with a pipe interface, a solenoid valve, a regulating valve, the temperature probe and the pressure probe;

[0022] The temperature probes are provided at both ends of the motor;

[0023] The vibration probes are provided in the X, Y and Z directions of the motor base;

[0024] The temperature probe is provided on the thrust bearing assembly;

[0025] The pressure probe is provided on the pump support, and the temperature probe is provided on the shaft seal and guide bearing in the pump support;

[0026] The vibration probes are provided in the X, Y and Z directions at the connection between the upper water pipe and the middle water pipe; the vibration probes are provided in the X and Y directions at the connection between the middle water pipe and the middle water pipe; the vibration probes are provided in the X and Y directions at the connection between the middle water pipe and the lower water pipe;

[0027] The temperature probe is provided at the guide bearings at the connection between the upper water pipe and the middle water pipe, the middle water pipe and the middle water pipe, and the middle water pipe and the lower water pipe;

[0028] The guide bearings in the guide vanes are each provided with the temperature probe; the guide vanes are connected to the pump cover at the X and Y directions with the vibration probes;

[0029] A wire tube is axially arranged between the casing and the outer wall of the upper water pipe, and the wires of the temperature probe, the vibration probe and the pressure probe are all inserted into the wire tube.

[0030] Compared with the prior art, the pump set for a nuclear power plant according to the embodiment of the present invention has the following beneficial effects:

[0031] The present invention proposes a nuclear power plant pump assembly, primarily for use within important plant water intake structures of AP1000 and CAP1400 nuclear power plants. The pump's submerged length is ≥6 meters. The pump assembly provided by the present invention is equipped with a casing, preventing the pump from directly contacting seawater flowing within the flow path of the plant's important plant water intake structure. Furthermore, the pump's mounting layer and the casing's mounting layer are not on the same mounting level. The weight of the motor and pump, as well as the weight of the casing, are independently borne by different mounting levels. This thoroughly resolves the technical drawbacks of existing pumps, such as high vibration and noise during operation, easy wear of motor bearings, oscillation at the joints of the upper, middle, and lower water pipes, and easy breakage of the upper water pipe and upper shaft at the pump support. This improves the operational safety and reliability of nuclear power plant pumps, extends the pump's service life, reduces the pump's operating, maintenance, and repair costs, and ensures the safe operation of the nuclear power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 This is a schematic structural diagram of a pump group for a nuclear power plant according to embodiment 1 of the present invention;

[0034] Figure 2 yes Figure 1 Enlarged view of point D in the middle;

[0035] Figure 3 yes Figure 2 Enlarged view of D2 in the middle;

[0036] Figure 4 yes Figure 2 Enlarged view of D1 in the middle;

[0037] Figure 5 yes Figure 1 Enlarged view of point F in the middle;

[0038] Figure 6 It is an enlarged schematic diagram of the filter screen and the casing in Example 1;

[0039] Figure 7 It is an enlarged schematic diagram of the filter screen and the casing in Example 2;

[0040] Figure 8 yes Figure 1 Enlarged view of point E in the middle;

[0041] Figure 9 yes Figure 1 Schematic diagram of the cross section at A-A in the middle;

[0042] Figure 10 yes Figure 1 Schematic diagram of the cross section at B-B in the middle;

[0043] Figure 11 This is a schematic structural diagram of a pump group for a nuclear power plant according to embodiment 3 of the present invention;

[0044] Figure 12 yes Figure 11 Enlarged view of point G in the middle;

[0045] Figure 13 yes Figure 12 Enlarged view of G1 in the middle;

[0046] Figure 14 yes Figure 12 Enlarged view of G2 in the middle;

[0047] Figure 15 yes Figure 11 Schematic diagram of the cross section at C-C in the middle;

[0048] In the figure, 1. pump assembly; 101. motor; 102. motor base; 103. pump support; 104. thrust bearing assembly; 105. upper water pipe; 106. middle water pipe; 107. lower water pipe; 108. water outlet horn; 109. guide vane; 110. pump cover; 111. filter screen; 112. corrugated hose; 113. shaft seal; 114. cooling pipe; 115. pipe joint; 116. regulating valve; 117. solenoid valve; 118, 119. wire tube; 120. reinforcement; 2. Casing; 201, strip filter hole; 3, first mounting assembly; 31, first mounting plate; 32, first bottom plate; 33, side mounting plate; 34, first mounting rib; 35, second mounting rib; 4, second mounting assembly; 41, second mounting plate; 42, anchor bolt; 5, flange; 601, first side plate; 602, first support rib; 603, second side plate; 604, second support rib; 701-711, temperature probe; 801-812, vibration probe; 901-902, pressure probe. DETAILED DESCRIPTION

[0049] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0050] In the description of the present invention, it should be understood that the terms "up", "down", "left", "right", "top", "bottom", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0051] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0052] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0053] Example 1

[0054] See also Figure 1 , is a pump group for a nuclear power plant in a preferred embodiment of the present invention, including a pump assembly 1, a casing 2, a first installation assembly 3 and a second installation assembly 4.

[0055] For details, see Figure 1 -10, the pump assembly 1 includes an electric motor 101, a motor base 102, a pump support 103, a thrust bearing assembly 104, a pump shaft (not shown), an upper water pipe 105, a middle water pipe 106, a lower water pipe 107, a water outlet horn 108, a guide vane 109, a pump cover 110 and a filter 111. Figure 2 The motor 101 is mounted on a motor base 102 and connected to the pump shaft. The motor base 102 is mounted on a pump support 103. The thrust bearing assembly 104 is passed through the pump shaft and connected to the pump support 103. Figure 1 The upper water pipe 105, the middle water pipe 106, and the lower water pipe 107 are connected in sequence through the bearing seat to form a water pipe. The upper end of the upper water pipe 105 is connected to the pump support 103, and the lower end of the lower water pipe 107 is connected to the water outlet horn 108. The pump shaft is located in the water pipe, and a shaft sleeve is installed outside the pump shaft at intervals. The guide bearing is located in the pump support 103 or the bearing seat and cooperates with the shaft sleeve. Figure 4 The water outlet speaker 108 is connected to the guide vane 109, the guide vane 109 is connected to the pump cover 110, and the pump cover 110 is connected to the filter screen 111. Figure 2 The outer wall of the upper water pipe 105 is provided with reinforcing ribs 120 along the axial direction.

[0056] For details, see Figure 2 and Figure 3A pump well is preset in soil layer 01, and an installation pit 02 is preset at the edge of the wellhead of the pump well.

[0057] The first mounting assembly 3 includes a first mounting plate 31 and a first base plate 32. The first mounting plate 31 is placed on the surface of the soil layer 01, with its inner edge flush with the wellhead of the pump well and its outer edge located at a position corresponding to the mounting pit 02. The first base plate 32 is located between the first mounting plate 31 and the soil layer 01. The second mounting assembly 4 includes a second mounting plate 41 and anchor bolts 42. The lower end of the anchor bolts 42 is located within the mounting pit 02, and the upper end of the anchor bolts 42 passes through the first mounting plate 31 and connects to the second mounting plate 41. The second mounting plate 41 is positioned at a predetermined height relative to the first mounting plate 31, and the inner edge of the second mounting plate 41 is horizontally spaced a predetermined distance from the inner edge of the first mounting plate 31.

[0058] A secondary soil layer 03 (concrete) is filled into the mounting pit 02 to simultaneously secure the first mounting plate 31, the second mounting plate 41, and the anchor bolts 42. The inner edge of the secondary soil layer is aligned with the inner edge of the second mounting plate 41 to form a secondary wellhead. After passing through the secondary wellhead and the wellhead, the casing is mounted on the first mounting plate 31 via flange 5. The pump assembly 1 is inserted into the casing 2, and the base plate of the pump support 103 is mounted on the second mounting plate 41, ensuring that the radial outer diameter of the pump assembly 1 does not contact the radial inner diameter of the casing 2.

[0059] For details, see Figure 5 and Figure 6 The bottom end of the casing 2 is a closed structure, the bottom end of the filter screen 111 is at a predetermined height from the bottom end of the casing 2, and the lower end of the casing 2 is provided with strip filter holes 201 at intervals along the circumferential direction. The arrow in the figure is the direction of water flow.

[0060] For details, see Figure 1 , a first side plate 601 and a first support rib 602 are further provided. The first side plate 601 is spaced apart and arranged on the inner wall of the pump well. The first support rib 602 is horizontally arranged between the first side plate 601 and the outer wall of the casing 2. In this embodiment, see Figure 9 and Figure 10 There are three groups of first side plates 601 and first supporting ribs 602 at equal intervals along the inner wall of the pump well, and there are three first supporting ribs 602 from top to bottom, which are respectively located at the corresponding positions of the upper water pipe 105, the middle water pipe 106 and the guide vane 109, and the highest point is located above the high liquid level 04, and the lowest point is located below the low liquid level 05.

[0061] For details, see Figure 1, a second side plate 603 and a second support rib 604 are also provided. The second side plate 603 is provided on the inner wall of the pump well, and the second support rib 604 is provided between the second side plate 603 and the outer wall of the casing 2, and forms an angle of 12°-75° with the horizontal plane, and the second support rib 604 is located at the corresponding position of the guide vane 109. In this embodiment, see Figure 9 and Figure 10 Three groups of second side plates 603 and second support ribs 604 are arranged at equal intervals along the inner wall of the pump well.

[0062] See also Figure 1 、 Figure 9 and Figure 10 The arrows in the figure indicate the direction of water flow, and the vortex represents tumbling water flow. In this embodiment, the casing 2 is fixed integrally to the primary soil layer 01, and the pump assembly 1 is vertically suspended within the casing 2. When the pump assembly 1 is stopped or running, it is not affected by any flow conditions of the seawater outside the casing 34. When the pump assembly 1 is operating to pump seawater, the seawater passes through the closed bottom end of the casing 2, is filtered and stabilized by the strip-shaped filter holes 201, and then flows into the filter screen 111. This ensures the cleanliness of the seawater pumped by the pump assembly 1 and the stability of its operation. This completely solves the technical defects of existing pumps, such as high vibration and noise, easy wear of motor bearings, oscillation at the joints of the upper, middle, and lower water pipes, and easy breakage of the upper water pipe and upper shaft at the pump support. This improves the operational safety and reliability of nuclear power plant pumps, extends the pump's service life, reduces the pump's operating, maintenance, and repair costs, and ensures the safe operation of the nuclear power plant.

[0063] Example 2

[0064] The differences between this embodiment and the first embodiment lie in the structure of the bottom end of the casing 2 and the structure between the pump cover 110 and the filter screen 111 .

[0065] See also Figure 7 In this embodiment, the bottom end of the casing 2 is an open structure, a corrugated hose 112 is provided between the pump cover 110 and the filter screen 111, and the bottom end of the casing 2 is flush with the contact surface of the corrugated hose 112 and the filter screen 11.

[0066] In this embodiment, the bottom end of the casing 2 is open. A corrugated hose 112 is installed between the pump cover 110 and the filter screen 111 of the pump assembly 1. The bottom end of the casing is aligned with the contact surface between the corrugated hose 112 and the filter screen 111. Except for the filter screen 111, which is exposed outside the casing 2, the entire pump assembly 1 is within the casing 2. When the pump assembly 1 is stopped or running, the filter screen 111 is affected by the flow of seawater outside the casing 2. The corrugated hose 112 eliminates the flow force of the seawater, ensuring normal operation and stopping of the pump assembly 1. This completely solves the technical defects of existing pumps such as high vibration and noise, easy wear of motor bearings, oscillation at the connection of the upper, middle, and lower water pipes, and easy breakage of the upper water pipe and upper shaft at the pump support. This improves the operational safety and reliability of nuclear power plant pumps, extends the pump's service life, reduces the operating, maintenance, and repair costs of the pump, and ensures the safe operation of the nuclear power plant.

[0067] Example 3

[0068] The difference between this embodiment and embodiment 1 lies in the structure and installation position of the first installation component 3 and the second installation component 4.

[0069] In this embodiment, see Figure 11 and Figure 12 The first mounting assembly 3 includes a first mounting plate 31, a side mounting plate 33, a first mounting rib 34 and a second mounting rib 35. Two side mounting plates 33 spaced at a predetermined height are provided on the inner wall of the pump well above the high liquid level 04. The first mounting rib 34 is horizontally provided on one of the side mounting plates 33, and the two ends of the second mounting rib 35 are respectively connected to the other side mounting plate 33 and the first mounting rib 34. The first mounting plate 31 is provided on the first mounting rib 34 and its inner edge is flush with the end of the first mounting rib 34. The second mounting rib 35 is located above the first mounting rib 34, and the second mounting rib 35 forms an angle of 15°-60° with the first mounting rib 34. In addition, at least three groups of the first mounting rib 34 and the second mounting rib 35 are evenly spaced along the inner wall of the pump well, see Figure 15 .

[0070] See also Figure 13 The second mounting assembly 4 includes a second mounting plate 41 and anchor bolts 42. The lower end of the anchor bolts 42 is located in the mounting pit 02, and the upper end is connected to the second mounting plate 41. The second mounting plate 41 is positioned on the surface of the primary soil layer 01. The secondary soil layer 03 is filled into the mounting pit 02 to secure the second mounting plate 41 and the anchor bolts 42.

[0071] During actual installation, flange 5 is welded to casing 2, side mounting plate 33 is bolted to the inner wall of the pump well, first mounting ribs 34 are evenly welded to side mounting plate 33 at a horizontal distribution, second mounting ribs 35 are evenly welded to side mounting plate 33 and first mounting ribs 34 at an angle, and first mounting plate 31 is welded to first mounting rib 34. Casing 2 is inserted through the wellhead and into first mounting plate 31, where flange 5 mates with first mounting plate 31 and is then bolted securely. Pump assembly 2 is inserted into the wellhead and casing 2, then secured to primary soil layer 01 and secondary soil layer 03. After pump assembly 1 is inserted into casing 2, ensure that its radial outer diameter does not contact the radial inner diameter of casing 2.

[0072] In this embodiment, the casing 2 is installed below the wellhead foundation layer and above the high liquid level 04. Within the pump well, above the high liquid level 04 is air, free from water flow impact, so this portion of the pumping pipe can be omitted. Because the material for the casing 2 is relatively expensive, this embodiment requires a shorter casing 2 compared to Example 1, saving costs. Furthermore, since the wellhead dimensions of the pump well are preset and fixed, the dimensions of the casing 2 may not necessarily match those of the wellhead. Compared to Example 1, this embodiment can address this mismatch.

[0073] Example 4

[0074] The difference between this embodiment and embodiment 3 is that embodiment 3 adopts the casing 2 structure with a closed bottom end in embodiment 1, while this embodiment adopts the casing 2 structure with an open bottom end in embodiment 2.

[0075] In the above embodiment, the pump assembly 1 is provided with a plurality of temperature probes, vibration probes and pressure probes.

[0076] For details, see Figure 2 , temperature probes 701 and 702 are respectively provided at both ends of the motor 101, and a vibration probe 801 in the X direction, a vibration probe 802 in the Y direction, and a vibration probe 803 in the Z direction are installed on the motor base 102. Figure 4 , a temperature probe 704 is installed on the thrust bearing assembly 104. The cooling pipe 114 passes through the pump support 103 and the motor base 102, connects the pump support 103 shaft seal 113 and the thrust bearing assembly 104, and is then connected to the bottom plate of the pump support 103. A pipe interface 115 is provided on the cooling pipe 114. A solenoid valve 117, a regulating valve 116, a pressure probe 901, and a temperature probe 703 are installed on the cooling pipe 114. A pressure probe 902 is installed on the pump support 103, and a temperature probe 705 and a guide bearing temperature probe 706 are installed on the pump support 103 shaft seal 113. See Figure 8The connection between the upper water pipe 105 and the middle water pipe 106 is equipped with an X-direction vibration probe 804, a Y-direction vibration probe 805, and a Z-direction vibration probe 806. Figure 1 Temperature probes 707 are installed on the guide bearings at the joints between the upper and middle water pipes 105, 106, and 106, and between the middle and lower water pipes 107. An X-direction vibration probe 807 and a Y-direction vibration probe 808 are installed at the joints between the middle and middle water pipes 106, and an X-direction vibration probe 809 and a Y-direction vibration probe 810 are installed at the joints between the middle and lower water pipes 107. Figure 5 The guide bearing in the guide vane 109 is equipped with temperature probes 708, 709, 710, and 711. The guide vane 109 at the pump cover 110 is provided with an X-direction vibration probe 811 and a Y-direction vibration probe 812. The wires of vibration probe 804, vibration probe 805, vibration probe 807, vibration probe 808, vibration probe 809, vibration probe 810, vibration probe 811 and vibration probe 812 pass through the wire tube 118, and the wire tube 118 passes through the bottom plate of the pump support 103 and is fixed on the guide vane 109, the lower water pipe 107, the middle water pipe 106 and the pump support 103 at the same time. The wires of vibration probe 806, temperature probe 707, temperature probe 711, temperature probe 710, temperature probe 709 and temperature probe 708 pass through the wire tube 119, and the wire tube 119 passes through the bottom plate of the pump support 103 and is fixed on the guide vane 109, the lower water pipe 107, the middle water pipe 106 and the pump support 103 at the same time. There are multiple middle water pipes 106 , temperature probes 707 , temperature probes 711 , temperature probes 710 , temperature probes 709 and temperature probes 708 , and the number of guide vanes 109 is ≥1.

[0077] Before the pump assembly starts, the central control computer issues a command to open solenoid valve 117 and regulating valve 116, allowing external water to enter the thrust bearing assembly 104, shaft seal 113, and guide bearing of pump assembly 1 for cooling and lubrication. When the solenoid valve 117 opens for a set time, the central control computer issues a command to activate motor 101 to start pump assembly 1. When pressure probe 902 detects a set pressure signal, the central control computer issues a command to close solenoid valve 117. Cooling and lubrication of the thrust bearing assembly 104, shaft seal 113, and guide bearing of pump assembly 1 are maintained by seawater pumped by pump assembly 1. If the operating conditions of the pipeline system change during operation of pump assembly 1 and pressure probe 901 detects a set high pressure signal, the central control computer issues a command to slowly close regulating valve 116 to adjust the pressure in cooling pipe 114 until pressure probe 901 detects the set pressure, at which point regulating valve 116 stops, maintaining normal pressure in the cooling coil of thrust bearing assembly 104 and ensuring the normal operation of pump assembly 1. When pressure probe 901 detects a set low pressure signal value, the central control computer issues a command to slowly open control valve 116 to adjust the pressure in cooling pipe 114 until pressure probe 901 detects the set value, at which point control valve 116 stops, maintaining normal pressure within the cooling coil of thrust bearing assembly 104 and ensuring the normal operation of pump assembly 1. If the operating conditions of the pipe network system of pump assembly 1 undergo a serious change during operation, such as when temperature probe 703 detects a set high temperature signal value, the central control computer issues a command to open solenoid valve 117 and control valve 116 until temperature probe 703 detects the set value, at which point control valve 116 stops. Solenoid valve 117 remains open until the pipe network system returns to normal. When temperature probe 703 detects the set high temperature signal value, the central control computer issues a command to adjust the pipe network system operating conditions. If no improvement is seen, pump assembly 1 stops operating.

[0078] During operation of pump assembly 1, vibration probe 801 detects the X-direction vibration value of motor 101 and motor base 102, vibration probe 802 detects the Y-direction vibration value of motor 101 and motor base 102, and vibration probe 803 detects the Z-direction vibration value of motor 101 and motor base 102. When each vibration probe detects the highest vibration signal value set, the central control computer issues a command to stop pump assembly 1. Vibration probe 804 detects the X-direction vibration value at the connection between upper water pipe 105 and middle water pipe 106, vibration probe 805 detects the Y-direction vibration value at the connection between upper water pipe 105 and middle water pipe 106, and vibration probe 806 detects the Z-direction vibration value at the connection between upper water pipe 105 and middle water pipe 106. When each vibration probe detects the highest vibration signal value set, the central control computer issues a command to stop pump assembly 1. Vibration probe 807 detects the X-direction vibration value at the junction of the middle and middle water pipes 106, while vibration probe 808 detects the Y-direction vibration value at the junction of the middle and middle water pipes 106. When each vibration probe detects the highest vibration signal value, the central control computer issues a command to stop pump assembly 1. Vibration probe 809 detects the X-direction vibration value at the junction of the middle and lower water pipes 107, while vibration probe 810 detects the Y-direction vibration value at the junction of the middle and lower water pipes 107. When each vibration probe detects the highest vibration signal value, the central control computer issues a command to stop pump assembly 1. Vibration probe 811 detects the X-direction vibration value of the guide vanes 109 at the lowest end of pump assembly 1, while vibration probe 812 detects the Y-direction vibration value of the guide vanes 109 at the lowest end of pump assembly 1. When each vibration probe detects the highest vibration signal value, the central control computer issues a command to stop pump assembly 1.

[0079] During operation, pump assembly 1 uses temperature probe 701 to monitor the temperature of the upper bearing of motor 101, and temperature probe 702 to monitor the temperature of the lower bearing of motor 101. When each temperature probe detects the highest temperature signal value, the central control computer issues a command to stop pump assembly 1. Temperature probe 704 monitors the bearing temperature of thrust bearing assembly 104. When the highest temperature signal value is reached, the central control computer issues a command to stop pump assembly 1. Temperature probe 705 monitors the temperature of shaft seal 113 of pump assembly 1. When the highest temperature signal value is reached, the central control computer issues a command to open solenoid valve 117. Solenoid valve 117 remains open until temperature probe 705 detects the set value, and pump assembly 1 operates normally. When temperature probe 705 detects the highest temperature signal value, the central control computer issues a command to stop pump assembly 1. Temperature probe 706 detects the guide bearing temperature at pump support 103, temperature probe 707 detects the guide bearing temperature at each pumping pipe connection, and temperature probes 708, 709, 710, and 711 detect the guide bearing temperature at each guide vane 109. When each temperature probe detects a set high temperature signal value, the central control computer issues a command to open solenoid valve 117. Solenoid valve 117 remains open until each temperature probe detects the set value, and pump assembly 1 operates normally. When each temperature probe detects the set maximum temperature signal value, the central control computer issues a command to stop pump assembly 1. Through the above technical processing, the actual operation of the pump can be monitored in real time, and operational problems at various locations of the pump can be identified, ensuring the safe use of the pump unit and the safe operation of the nuclear power plant.

[0080] In summary, the present invention proposes a nuclear power plant pump assembly, primarily for use within critical water intake structures in AP1000 and CAP1400 nuclear power plants. The pump has a submerged length of 6 meters or greater. The pump motor is protected from axial forces, and the pump's probes and valves are connected to the plant's central control room computer, enabling real-time monitoring of the pump's operation and identifying any pump problems. The nuclear power plant pump assembly provided by the present invention is equipped with a casing, preventing the pump from direct contact with seawater flowing within the plant's critical water intake structures. Furthermore, the pump's mounting layer and the casing's mounting layer are not located on the same mounting level, allowing the weight of the motor and pump to be independently borne by the casing at different mounting levels. This completely resolves the technical drawbacks of existing pumps, such as high vibration and noise, prone to motor bearing wear, oscillation at the connections between the upper, middle, and lower water pipes, and prone to breakage of the upper water pipe and upper shaft at the pump support. This improves the operational safety and reliability of nuclear power plant pumps, extends the pump's service life, reduces pump operation, maintenance, and repair costs, and ensures the safe operation of the nuclear power plant.

[0081] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A pump set for a nuclear power plant, characterized in that: The pump assembly includes a motor, a motor base, a pump support, a thrust bearing assembly, a pump shaft, an upper water pipe, a middle water pipe, a lower water pipe, a water outlet horn, a guide vane, a pump cover and a filter screen; The electric motor is mounted on the motor base and connected to the pump shaft, and the motor base is mounted on the pump support; the thrust bearing assembly is passed through the pump shaft and connected to the pump support; the upper water pipe, the middle water pipe, and the lower water pipe are sequentially connected to form a water pipe, the upper end of the upper water pipe is connected to the pump support, and the lower end of the lower water pipe is connected to the water outlet horn; the water outlet horn is connected to the guide vane, the guide vane is connected to the pump cover, and the pump cover is connected to the filter screen; Also included is a casing, a first mounting assembly, and a second mounting assembly; The primary soil layer is preset with a pump well; The first mounting assembly is connected to the surface or inner wall of the primary soil layer, and the casing is mounted on the first mounting assembly; An installation pit is preset at the edge of the wellhead of the pump well, the second installation assembly is located at a predetermined position of the installation pit, a secondary soil layer is filled into the installation pit to fix the second installation assembly, so that the second installation assembly and the first installation assembly are located at different installation levels, and the pump assembly is installed on the second installation assembly through the pump support after passing through the casing; The first mounting assembly includes a first mounting plate and a first bottom plate; the first mounting plate is placed on the surface of the primary soil layer, and its inner edge is flush with the wellhead of the pump well, and its outer edge is located at the corresponding position of the mounting pit; the first bottom plate is located between the first mounting plate and the primary soil layer, The first mounting assembly further includes a side mounting plate, a first mounting rib, and a second mounting rib; two side mounting plates spaced at a predetermined height are provided on the inner wall of the pump well located above the high liquid level; the first mounting rib is horizontally provided on one of the side mounting plates; the two ends of the second mounting rib are respectively connected to the other side mounting plate and the first mounting rib, and the second mounting rib forms an angle of 15°-60° with the first mounting rib; the first mounting plate is provided on the first mounting rib, and its inner edge is flush with the end of the first mounting rib; and at least three groups of the first mounting rib and the second mounting rib are provided at equal intervals along the inner wall of the pump well; the casing is installed on the first mounting plate after passing through the wellhead; The second mounting assembly includes a second mounting plate and anchor bolts; The lower end of the anchor bolt is located in the mounting groove, and the upper end thereof passes through the first mounting plate and is connected to the second mounting plate, so that there is a predetermined height between the second mounting plate and the first mounting plate, and the inner edge of the second mounting plate is horizontally spaced a predetermined distance from the inner edge of the first mounting plate, and the mounting groove is filled with a secondary soil layer to simultaneously fix the first mounting plate, the second mounting plate and the anchor bolt, and the inner edge of the secondary soil layer is flush with the inner edge of the second mounting plate to form a secondary wellhead, the casing is installed on the first mounting plate after passing through the secondary wellhead and the wellhead, and the pump support is installed on the second mounting plate, or, The upper end of the anchor bolt is connected to the second mounting plate, so that the second mounting plate is located on the surface of the primary soil layer, and the secondary soil layer is filled into the mounting pit to fix the second mounting plate and the anchor bolt, and the pump support is installed on the second mounting plate.

2. The nuclear power plant pump assembly according to claim 1, characterized in that: The bottom end of the casing is a closed structure, the bottom end of the filter screen is at a predetermined height from the bottom end of the casing, and the lower end of the casing is provided with filter holes spaced circumferentially.

3. The nuclear power plant pump assembly according to claim 2, characterized in that: The filter holes are strip-shaped filter holes.

4. The nuclear power plant pump assembly according to claim 1, characterized in that: The bottom end of the casing is an open structure, a hose is provided between the pump cover and the filter screen, and the bottom end of the casing is flush with the contact surface of the hose and the filter screen.

5. The pump assembly for nuclear power plant according to claim 1, characterized in that: The outer wall of the upper water pipe is provided with reinforcing ribs along the axial direction.

6. The pump assembly for nuclear power plant according to claim 1, characterized in that: A first side plate and a first support rib are also provided; the first side plate is provided on the inner wall of the pump well, and the first support rib is horizontally provided between the first side plate and the outer wall of the casing; and at least three groups of the first side plates and the first support rib are provided at equal intervals along the inner wall of the pump well.

7. The nuclear power plant pump assembly according to claim 6, characterized in that: A second side plate and a second support rib are also provided; the second side plate is provided on the inner wall of the pump well, the second support rib is provided between the second side plate and the outer wall of the casing, and forms an angle of 12°-75° with the horizontal plane, and the second support rib is located at the corresponding position of the guide vane; at least three groups of the second side plates and the second support rib are provided at equal intervals along the inner wall of the pump well.

8. The pump assembly for nuclear power plant according to claim 1, characterized in that: The pump assembly is provided with a number of temperature probes, vibration probes and pressure probes; A shaft seal is provided in the pump support, a cooling coil is provided in the thrust bearing assembly, and a cooling pipe is provided to connect the cooling coil and the shaft seal, and the cooling pipe is provided with a pipe interface, a solenoid valve, a regulating valve, the temperature probe and the pressure probe; The temperature probes are provided at both ends of the motor; The vibration probes are provided in the X, Y and Z directions of the motor base; The temperature probe is provided on the thrust bearing assembly; The pressure probe is provided on the pump support, and the temperature probe is provided on the shaft seal and guide bearing in the pump support; The vibration probes are provided in the X, Y and Z directions at the connection between the upper water pipe and the middle water pipe; the vibration probes are provided in the X and Y directions at the connection between the middle water pipe and the middle water pipe; the vibration probes are provided in the X and Y directions at the connection between the middle water pipe and the lower water pipe; The temperature probe is provided at the guide bearings at the connection between the upper water pipe and the middle water pipe, the middle water pipe and the middle water pipe, and the middle water pipe and the lower water pipe; The guide bearings in the guide vanes are each provided with the temperature probe; the guide vanes are connected to the pump cover at the X and Y directions with the vibration probes; A wire tube is axially arranged between the casing and the outer wall of the upper water pipe, and the wires of the temperature probe, the vibration probe and the pressure probe are all inserted into the wire tube.

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