Nuclear power unit oxidation purification system

Abstract

The utility model discloses an oxidation purification system of a nuclear power unit, which comprises a system interface, a first pressure regulating valve, a capacity control box, a charging pump, a low-pressure discharge pipeline, a purification pipeline, a charging pipeline and a bypass pipeline, the two ends of the purification pipeline are connected to the first pressure regulating valve and the capacity control box respectively, and the two ends of the charging pipeline are connected to the capacity control box and the charging pump respectively. According to the nuclear power unit oxidation purification system, the system structure is optimized through redundancy design, the safety and reliability of system operation and the maintainability of the system are guaranteed, part of equipment can adapt to the hydraulic characteristics and operation requirements of the improved system after being redesigned, the purification flow can be improved, the overhaul period can be shortened after optimization, and the maintenance cost is reduced. The economic benefit is obvious.

Description

Technical Field

[0001] The utility model relates to the field of oxidation purification of nuclear power plants, in particular to an oxidation purification system for nuclear power units. Background Art

[0002] The optimization of nuclear power plant overhaul period has received increasing attention in recent years. Carrying out overhaul optimization is an effective and important way to reduce operating costs, improve unit availability and core competitiveness. Shortening the overhaul period and reducing overhaul costs are requirements of nuclear power plant development planning. The reference plan and actual overhaul period of the ten-year overhaul / first refueling overhaul, conventional overhaul and short-term overhaul of each nuclear power unit are significantly different from those of the same type of three-loop pressurized water reactor units in the United States. During the shutdown and refueling period, the current system oxidation purification effect does not meet the demand and cannot meet the predetermined operating requirements. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide an oxidation purification system for a nuclear power unit.

[0004] The utility model solves the technical problem by adopting the following technical solution: constructing a nuclear power unit oxidation purification system, which includes a system interface, a first pressure regulating valve, a volume control box, an upper charging pump, a low-pressure lowering pipeline, a purification pipeline, an upper charging pipeline and a bypass pipeline;

[0005] The two ends of the low-pressure discharge pipeline are respectively connected to the system interface and the first pressure regulating valve, the two ends of the purification pipeline are respectively connected to the first pressure regulating valve and the volume control box, and the two ends of the charging pipeline are respectively connected to the volume control box and the charging pump;

[0006] The low-pressure discharge pipeline is provided with a first filter, the purification pipeline is provided with a desalination bed and a second filter, the first end of the bypass pipeline is connected to the first pressure regulating valve, and the second end of the bypass pipeline is connected to the purification pipeline after the second filter.

[0007] In some embodiments, the low-pressure discharge pipeline is provided with a first pressure gauge, an isolation valve, a second pressure regulating valve, a first safety valve, a first heat exchanger, a second pressure gauge, a first flow meter, a third pressure regulating valve, a second safety valve and a third safety valve in sequence along the liquid flow direction thereof, and the first filter is located between the third safety valve and the first pressure regulating valve.

[0008] In some embodiments, the low-pressure discharge pipeline is further connected to an output pipeline, the output pipeline is connected between the first pressure gauge and the isolation valve, and one end of the output pipeline away from the low-pressure discharge pipeline is connected to the RRA system.

[0009] In some embodiments, the purification pipeline is provided with a fourth pressure regulating valve, a fifth pressure regulating valve and a sixth pressure regulating valve in sequence along the liquid flow direction thereof;

[0010] The fourth pressure regulating valve is located between the first pressure regulating valve and the desalination bed, the fifth pressure regulating valve is located between the desalination bed and the second filter, the sixth pressure regulating valve is located between the second filter and the control box, and a fourth safety valve is also provided between the sixth pressure regulating valve and the second filter.

[0011] In some embodiments, the sixth pressure regulating valve is further connected to a discharge pipeline, and one end of the discharge pipeline away from the sixth pressure regulating valve is connected to the TEP system.

[0012] In some embodiments, the control box is also connected to a discharge pipeline and a third pressure gauge, and a fifth safety valve and a sixth safety valve are provided on the discharge pipeline.

[0013] In some embodiments, a seventh pressure regulating valve and a fourth pressure gauge are provided on the filling pipeline along the liquid flow direction thereof.

[0014] In some embodiments, the charging pipeline is respectively connected to the main pump shaft seal injection pipeline and the cold section pipeline after passing through the charging pump.

[0015] In some embodiments, the main pump shaft seal injection pipeline is provided with an eighth pressure regulating valve, a duplex filter assembly, a second flow meter and a water pump shaft seal chamber in sequence along its liquid flow direction;

[0016] The duplex filter assembly includes a third filter and a fourth filter which are arranged in parallel.

[0017] In some embodiments, the cold section pipeline is provided with a third flow meter, a fifth pressure gauge, a ninth pressure regulating valve, a second heat exchanger and a terminal cold source in sequence along the liquid flow direction thereof.

[0018] The implementation of the utility model has the following beneficial effects: the oxidation purification system of the nuclear power unit ensures the safety and reliability of the system operation and the maintainability of the system through redundant design and optimized system structure, so that some equipment can adapt to the improved system hydraulic characteristics and operation requirements after redesign, and the purification flow can be increased. After optimization, the overhaul period can be saved, and the economic benefits are obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solution of the utility model, the utility model will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the following drawings only show certain embodiments of the utility model, and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0020] Figure 1 It is a schematic diagram of the overall structure of the oxidation purification system of a nuclear power unit in some embodiments of the utility model. DETAILED DESCRIPTION

[0021] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, are constructed and operated in a specific direction, and are only for the convenience of describing the present technical solution, rather than indicating that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation to the present invention.

[0022] It should also be noted that, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.

[0023] See also Figure 1, is an oxidation purification system for a nuclear power unit in some embodiments of the utility model, which is used for oxidation purification of corrosion products introduced from the outside. The oxidation purification system for a nuclear power unit comprises a system interface 1, a first pressure regulating valve 2, a capacity control box 3, an upper charging pump 4, a low-pressure discharge pipeline 5, a purification pipeline 6, an upper charging pipeline 7 and a bypass pipeline 8. The two ends of the low-pressure discharge pipeline 5 are respectively connected to the system interface 1 and the first pressure regulating valve 2, the two ends of the purification pipeline 6 are respectively connected to the first pressure regulating valve 2 and the capacity control box 3, and the two ends of the upper charging pipeline 7 are respectively connected to the capacity control box 3 and the upper charging pump 4.

[0024] Specifically, the system interface 1 is used to connect with external equipment, so as to introduce corrosion products into the oxidation purification system of the nuclear power unit for purification, the first pressure regulating valve 2 is used to adjust the flow pressure, the control box 3 can be used as a degassing tower, so that the radioactive gas generated by the corrosion products is released from there and discharged to the exhaust gas treatment system regularly, and can also be used as a high-level water supply tank for the charging pump 4 to provide a water source for the charging pump 4. The charging pump 4 can supplement the primary circuit with the charging water containing boric acid when the reactor is operating normally, stabilize the pressure of the circuit system, and provide mechanical seal cooling water to the main pump to ensure the normal operation of the mechanical seal of the main pump and prevent the leakage of radioactive primary circuit water in the main pump.

[0025] In addition, the low-pressure discharge pipeline 5 is provided with a first filter 501, and the purification pipeline 6 is provided with a desalting bed 61 and a second filter 62. The first filter 501 and the second filter 62 are used to filter the introduced corrosion products, and the desalting bed 61 can soften and desalt the introduced corrosion products to prevent the accumulation of scale and salt scale in the subsequent devices. The first end of the bypass pipeline 8 is connected to the first pressure regulating valve 2, and the second end of the bypass pipeline 8 is connected to the purification pipeline 6 after the second filter 62. When the introduced corrosion products meet the production requirements after filtering by the first filter 501 and do not need to be processed by the desalting bed 61, they can directly flow through the bypass pipeline 8 to the purification pipeline 6 after the second filter 62, thereby improving the purification efficiency.

[0026] More specifically, the low-pressure discharge pipeline 5 is provided with a first pressure gauge 502, an isolation valve 503, a second pressure regulating valve 504, a first safety valve 505, a first heat exchanger 506, a second pressure gauge 507, a first flow meter 508, a third pressure regulating valve 509, a second safety valve 510 and a third safety valve 511 in sequence along the liquid flow direction thereof, and the first filter 501 is located between the third safety valve 511 and the first pressure regulating valve 2. The first pressure gauge 502 is used to measure the pressure value of the low-pressure discharge pipeline 5 after the system interface 1 introduces the corrosion product, the isolation valve 503 is used to control the on-off of the inflow of the corrosion product, the second pressure regulating valve 504 and the third pressure regulating valve 509 are used to adjust the pressure, the first heat exchanger 506 is used to exchange heat for the corrosion product, the first flow meter 508 is used to measure the flow value of the low-pressure discharge pipeline 5, the first safety valve 505, the second safety valve 510 and the third safety valve 511 can protect the safety of the system. When the pressure in the equipment or pipeline exceeds the set pressure of the safety valve, the pressure relief is automatically opened to ensure that the medium pressure in the equipment and pipeline is below the set pressure, protect the normal operation of the equipment and pipeline, prevent accidents, and reduce losses. Among them, the second safety valve 510 and the third safety valve 511 have different starting pressures and can control different system safety pressures.

[0027] The low-pressure discharge pipeline 5 is also connected to an output pipeline 512, which is connected between the first pressure gauge 502 and the isolation valve 503, and one end of the output pipeline 512 away from the low-pressure discharge pipeline 5 is connected to the RRA system 513. The RRA system 513 refers to a waste heat removal system, and part of the heat of the corrosion products introduced from the system interface 1 is discharged to the waste heat removal system through the output pipeline 512.

[0028] Furthermore, the purification pipeline 6 is provided with a fourth pressure regulating valve 63, a fifth pressure regulating valve 64 and a sixth pressure regulating valve 65 in sequence along the liquid flow direction thereof, the fourth pressure regulating valve 63 is located between the first pressure regulating valve 2 and the desalting bed 61, the fifth pressure regulating valve 64 is located between the desalting bed 61 and the second filter 62, the sixth pressure regulating valve 65 is located between the second filter 62 and the control box 3, and a fourth safety valve 66 is further provided between the sixth pressure regulating valve 65 and the second filter 62. The fourth pressure regulating valve 63, the fifth pressure regulating valve 64 and the sixth pressure regulating valve 65 can adjust the pressure at their respective positions to facilitate the control of the pressure value of the corrosion products during the purification process.

[0029] The sixth pressure regulating valve 65 is also connected to a discharge pipeline 67, and one end of the discharge pipeline 67 away from the sixth pressure regulating valve 65 is connected to a TEP system 68, which refers to a desalination system. It can be understood that after the corrosion products are filtered by the filter or the desalination bed 61, a part of the corrosion products flows to another desalination system for further filtering and softening after passing through the sixth pressure regulating valve 65.

[0030] The control box 3 is also connected to a discharge pipeline 31 and a third pressure gauge 32. When the control box 3 is depressurized, the pressure is discharged to the atmosphere through the discharge pipeline 31. A fifth safety valve 311 and a sixth safety valve 312 are provided on the discharge pipeline 31. The fifth safety valve 311 and the sixth safety valve 312 have different tripping pressures and can control different system safety pressures.

[0031] A seventh pressure regulating valve 71 and a fourth pressure gauge 72 are provided on the charging pipeline 7 along the liquid flow direction thereof to facilitate pressure adjustment and measurement of the pressure value of the charging pipeline 7. A sixth pressure gauge 41 is also provided on the pipeline after the charging pump 4.

[0032] Furthermore, the upper filling pipeline 7 is connected to the main pump shaft seal injection pipeline 73 and the cold section pipeline 74 respectively after passing through the upper filling pump 4. The liquid after passing through the upper filling pump 4 is divided into two paths and enters the main pump shaft seal injection pipeline 73 and the cold section pipeline 74 respectively. The main pump shaft seal injection pipeline 73 is provided with an eighth pressure regulating valve 731, a double filter assembly, a second flow meter 732 and a water pump shaft seal chamber 733 in sequence along the liquid flow direction. The double filter assembly includes a third filter 734 and a fourth filter 735 arranged in parallel. Its structure has good sealing performance, strong flow capacity, simple operation, wide application range and strong adaptability. The water pump shaft seal chamber 733 can be used to seal liquid to prevent liquid leakage. The liquid in the water pump shaft seal chamber 733 can be pushed toward the outlet direction through the water pump and transported to other systems for use.

[0033] In addition, the cold section pipeline 74 is provided with a third flow meter 741, a fifth pressure gauge 742, a ninth pressure regulating valve 743, a second heat exchanger 744 and a terminal cold source 745 in sequence along the liquid flow direction. The water entering the cold section pipeline 74 is converted into chilled water after passing through the second heat exchanger 744 and enters the terminal cold source 745 for storage for use by other systems.

[0034] In general, when the overall flow of the oxidation purification system of the nuclear power unit needs to be increased, an indicator instrument is required to display the actual flow of the system. The oxidation purification system of the nuclear power unit is equipped with multiple pressure gauges and flow meters to monitor the pressure and flow of each pipeline. It can monitor the operating status of the system in real time through pressure and flow measurement, and can transmit data to the main control room in real time through a wireless network. The flow and pressure of the unit are controlled in the main control room, and the pressure is adjusted by multiple pressure regulating valves. After the purification flow increases, the charging pump 4 will automatically adjust the outlet head according to its hydraulic characteristic curve, so it has no effect on the hydraulic characteristics of the charging pump 4.

[0035] It can be understood that the oxidation purification system of the nuclear power unit ensures the safety and reliability of the system operation, as well as the maintainability of the system through redundant design and optimized system structure, so that some equipment can be redesigned to adapt to the improved system hydraulic characteristics and operating requirements, which can increase the purification flow rate. After optimization, it can save overhaul time and have obvious economic benefits.

[0036] It can be understood that the above embodiments only express the preferred implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the utility model. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the utility model, the above-mentioned technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the utility model. Therefore, all equivalent changes and modifications made to the scope of the claims of the utility model should fall within the scope of the claims of the utility model.

Claims

1. A nuclear power unit oxidation purification system, characterized in that: It comprises a system interface (1), a first pressure regulating valve (2), a volume control box (3), a charging pump (4), a low-pressure discharge pipeline (5), a purification pipeline (6), a charging pipeline (7) and a bypass pipeline (8); The two ends of the low-pressure discharge pipeline (5) are respectively connected to the system interface (1) and the first pressure regulating valve (2), the two ends of the purification pipeline (6) are respectively connected to the first pressure regulating valve (2) and the volume control box (3), and the two ends of the charging pipeline (7) are respectively connected to the volume control box (3) and the charging pump (4); The low-pressure discharge pipeline (5) is provided with a first filter (501), the purification pipeline (6) is provided with a desalination bed (61) and a second filter (62), the first end of the bypass pipeline (8) is connected to the first pressure regulating valve (2), and the second end of the bypass pipeline (8) is connected to the purification pipeline (6) after the second filter (62).

2. The nuclear power unit oxidation purification system according to claim 1, characterized in that: The low-pressure discharge pipeline (5) is provided with a first pressure gauge (502), an isolation valve (503), a second pressure regulating valve (504), a first safety valve (505), a first heat exchanger (506), a second pressure gauge (507), a first flow meter (508), a third pressure regulating valve (509), a second safety valve (510) and a third safety valve (511) in sequence along the liquid flow direction thereof, and the first filter (501) is located between the third safety valve (511) and the first pressure regulating valve (2).

3. The nuclear power unit oxidation purification system according to claim 2, characterized in that: The low-pressure discharge pipeline (5) is also connected to an output pipeline (512), and the output pipeline (512) is connected between the first pressure gauge (502) and the isolation valve (503). One end of the output pipeline (512) away from the low-pressure discharge pipeline (5) is connected to the RRA system (513).

4. The nuclear power unit oxidation purification system according to claim 1, characterized in that: The purification pipeline (6) is provided with a fourth pressure regulating valve (63), a fifth pressure regulating valve (64) and a sixth pressure regulating valve (65) in sequence along the liquid flow direction thereof; The fourth pressure regulating valve (63) is located between the first pressure regulating valve (2) and the desalting bed (61), the fifth pressure regulating valve (64) is located between the desalting bed (61) and the second filter (62), the sixth pressure regulating valve (65) is located between the second filter (62) and the control box (3), and a fourth safety valve (66) is also provided between the sixth pressure regulating valve (65) and the second filter (62).

5. The oxidation purification system of a nuclear power unit according to claim 4, characterized in that: The sixth pressure regulating valve (65) is also connected to a discharge pipeline (67), and one end of the discharge pipeline (67) away from the sixth pressure regulating valve (65) is connected to a TEP system (68).

6. The nuclear power unit oxidation purification system according to claim 1, characterized in that: The control box (3) is also connected to a discharge pipeline (31) and a third pressure gauge (32), and the discharge pipeline (31) is provided with a fifth safety valve (311) and a sixth safety valve (312).

7. The oxidation purification system of a nuclear power unit according to claim 1, characterized in that: A seventh pressure regulating valve (71) and a fourth pressure gauge (72) are provided on the upper filling pipeline (7) along the liquid flow direction thereof.

8. The nuclear power unit oxidation purification system according to claim 1, characterized in that: The upper charging pipeline (7) is respectively connected to a main pump shaft seal injection pipeline (73) and a cold section pipeline (74) after passing through the upper charging pump (4).

9. The nuclear power unit oxidation purification system according to claim 8, characterized in that: The main pump shaft seal injection pipeline (73) is provided with an eighth pressure regulating valve (731), a duplex filter assembly, a second flow meter (732) and a water pump shaft seal chamber (733) in sequence along the liquid flow direction thereof; The duplex filter assembly includes a third filter (734) and a fourth filter (735) arranged in parallel.

10. The nuclear power unit oxidation purification system according to claim 8, characterized in that: The cold section pipeline (74) is provided with a third flow meter (741), a fifth pressure gauge (742), a ninth pressure regulating valve (743), a second heat exchanger (744) and a terminal cold source (745) in sequence along the liquid flow direction thereof.

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