A floating reactor injection system to improve the reliability of closed pipe sections

Abstract

The present invention discloses a floating reactor safety injection system for improving the reliability of closed pipe sections, and relates to the technical field of special safety facilities for floating reactors; it includes a main pipeline hot pipe section and a main pipeline cold pipe section, each main pipeline hot pipe section is provided with a hot isolation valve, and each main pipeline cold pipe section is provided with a cold isolation valve; all hot isolation valves and cold isolation valves are connected to the electric isolation valve of the safety injection system through the same safety injection system isolation valve; a first pneumatic isolation valve is provided on the 1# closed pipe section, and a second pneumatic isolation valve is provided on the 2# closed pipe section; the first pneumatic isolation valve and the second pneumatic isolation valve are both connected to the same pressure relief box. When the isolation valve of the 1# closed pipe and / or the 2# closed pipe leaks, the present invention can timely relieve the pressure of the closed pipe section, which not only avoids cracks in the closed pipe section due to fatigue damage, significantly improves the reliability of the closed pipe section, but also can collect and process radioactive media in a unified manner.

Description

Technical Field

[0001] The invention relates to the technical field of special safety facilities for floating reactors, and in particular to a floating reactor safety injection system for improving the reliability of closed pipe sections. Background Art

[0002] At present, according to the feedback from the operating experience of onshore nuclear power plants, it was found that low-temperature water accidentally entered the primary circuit from the high-pressure injection pipeline, causing thermal fatigue cracks and leakage in the pipe section between the reactor coolant system check valve and the main pipeline. The reason for this phenomenon is that the isolation valve of the high-pressure injection circuit leaked, causing cold water to enter the primary circuit. The cold and hot water mixed in the pipeline downstream of the reactor coolant system check valve, causing thermal fatigue cracks in the pipe wall. The operating experience of similar nuclear power units at home and abroad shows that there is a possibility of leakage in the isolation valve between the injection system and the main pipeline. This leakage can be divided into two situations: leakage from the injection system to the primary circuit and leakage from the primary circuit to the injection system.

[0003] For the floating reactor injection system, the leakage is mainly from the primary circuit to the injection system. The leakage is caused by the failure or wear of the check valve, which causes the high-temperature and high-pressure fluid of the primary circuit to enter the isolated part of the closed pipe section and mix with the low-temperature and low-pressure fluid. The upstream part of the leaking check valve (near the injection system side) will cause the temperature to rise due to the accelerated flow rate, and the downstream (near the reactor coolant system side) will also increase the temperature due to the replenishment of higher temperature fluid. This leakage may occur repeatedly due to changes in the state of the primary circuit or valve instability. The temperature fluctuations on both sides of the check valve will generate cyclic heat loads on the pipeline. The cyclic heat loads generated by the sudden change of fluid temperature will cause fatigue in the closed pipe sections of the isolated part and the unisolated part. Once the closed pipe section suffers fatigue damage and cracks appear, the depth and range of the cracks will continue to increase, which may eventually cause the pipeline to rupture and cause a loss of coolant in the primary circuit. Summary of the invention

[0004] In view of the defects existing in the prior art, the technical problem solved by the present invention is: when the check valve of the floating reactor injection system leaks, how to relieve the pressure of the closed pipe section to avoid cracks in the closed pipe section due to fatigue damage, thereby improving the reliability of the closed pipe section.

[0005] To achieve the above objectives, the present invention provides a floating reactor safety injection system for improving the reliability of closed pipe sections, including a reactor compartment, in which a safety injection system body and a reactor coolant system are arranged; the reactor coolant system includes two closed loop systems, each loop system includes a main pipeline hot pipe section and a main pipeline cold pipe section, each main pipeline hot pipe section is provided with a hot isolation valve, and each main pipeline cold pipe section is provided with a cold isolation valve; all hot isolation valves and cold isolation valves are connected to the electric isolation valve of the safety injection system through the same safety injection system isolation valve; the pipe section between all hot and cold isolation valves and the safety injection system isolation valve is defined as 1# closed pipe section, and the pipe section between the safety injection system isolation valve and the electric isolation valve of the safety injection system is defined as 2# closed pipe section; a first pneumatic isolation valve is provided on the 1# closed pipe section, and a second pneumatic isolation valve is provided on the 2# closed pipe section; the first pneumatic isolation valve and the second pneumatic isolation valve are both connected to the same pressure relief box.

[0006] On the basis of the above technical solution, the loop system specifically includes:

[0007] Reactor pressure vessel, used to contain the reactor core components, ensure the integrity of the coolant pressure boundary, and prevent the release of radioactive materials into the containment;

[0008] The main pipeline hot pipe section is used to connect the outlet of the reactor pressure vessel and the inlet of the steam generator;

[0009] Steam generators, which carry away the heat generated by the reactor core;

[0010] The main pipeline transition section is used to connect the outlet of the steam generator and the inlet of the main pump;

[0011] Main pumps, used to provide the driving head of the reactor coolant;

[0012] The main pipeline cold section is used to connect the inlet of the reactor pressure vessel and the outlet of the main pump.

[0013] On the basis of the above technical solution, a pressure stabilizer is connected to the hot pipe section of the main pipeline of any one of the loop systems, which is used to stabilize the pressure of the reactor coolant system.

[0014] On the basis of the above technical solution, the main body of the injection system specifically includes the following connected in sequence:

[0015] Cooling water tank, used to store cooling water used for injection;

[0016] An injection pump is used to provide driving force for injection water;

[0017] Electric isolation valve, used to isolate the injection pump.

[0018] On the basis of the above technical solution, a first pressure measuring instrument is provided on the 1# closed pipe section, which is used to control the first pneumatic isolation valve to open when the pressure in the 1# closed pipe section exceeds the specified threshold; a second pressure measuring instrument is provided on the 2# closed pipe section; which is used to control the electric isolation valve to close and open the first pneumatic isolation valve and the second pneumatic isolation valve at the same time when the pressure in the 2# closed pipe section exceeds the specified threshold.

[0019] On the basis of the above technical solution, the pressure relief box uses available equipment for recovering and discharging radioactive media.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] (1) When leakage occurs in the isolation valve of the 1# closed pipeline and / or the 2# closed pipeline, the present invention can timely relieve the pressure of the closed pipe section through a simple and practical connection structure, which not only avoids cracks in the closed pipe section due to fatigue damage, significantly improves the reliability of the closed pipe section, but also can uniformly collect and process radioactive media, avoiding the release of radioactive media into the containment.

[0022] (2) The design of the present invention can reduce the number of special facilities for overpressure discharge of radioactive media in the collection pipeline and the connected pipelines and other accessories, which is beneficial to reducing the weight of the hull and saving space in the containment. Therefore, the simple and compact structure of the present invention significantly improves the utilization rate of system equipment, is easy to install and maintain, saves space on board, and is suitable for environmental conditions where the floating reactor space is limited. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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 description of the embodiments. 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 creative work.

[0024] Figure 1 It is a structural schematic diagram of a floating reactor injection system for improving the reliability of a closed pipe section in an embodiment of the present invention.

[0025] In the figure: 1-reactor pressure vessel, 2-steam generator, 3-hot pipe section of main pipeline, 4-stabilizer, 5-main pump, 6-transition section of main pipeline, 7-cold pipe section of main pipeline, 8-hot isolation valve, 9-cold isolation valve, 10-first pressure measuring instrument, 11-injection system isolation valve, 12-second pneumatic isolation valve, 13-first pneumatic isolation valve, 14-second pressure measuring instrument, 15-electric isolation valve, 16-injection pump, 17-cooling water tank, 18-combination, 19-pressure relief tank. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0027] The floating reactor safety injection system for improving the reliability of the closed pipe section in the embodiment of the present invention includes a reactor compartment 18, in which a safety injection system body and a reactor coolant system are arranged. Figure 1 As shown, the reactor coolant system includes two closed loop systems, each loop system includes:

[0028] Reactor pressure vessel 1, used to contain the reactor core components, ensure the integrity of the coolant pressure boundary, and prevent the release of radioactive materials into the containment;

[0029] The main pipeline heat pipe section 3 is used to connect the outlet of the reactor pressure vessel 1 and the inlet of the steam generator 2, and at the same time, as a component of the pressure boundary of the primary loop system, participates in forming a safety barrier containing radioactive materials;

[0030] Steam generator 2 is used to remove the heat generated by the reactor core, forming a primary circuit pressure boundary to prevent radioactive substances from leaking into the containment and secondary circuit system;

[0031] The main pipeline transition section 6 is used to connect the outlet of the steam generator 2 and the inlet of the main pump 5, and at the same time, as a component of the pressure boundary of the primary circuit system, participates in forming a safety barrier containing radioactive materials;

[0032] A main pump 5, used to provide a driving pressure head for the reactor coolant to ensure the circulation of the reactor coolant;

[0033] The main pipeline cold pipe section 7 is used to connect the inlet of the reactor pressure vessel 1 and the outlet of the main pump 5. At the same time, as a component of the pressure boundary of the primary loop system, it participates in forming a safety barrier to contain radioactive materials.

[0034] A pressurizer 4 is connected to the main pipeline hot pipe section 3 of any loop, which is used to stabilize the pressure of the reactor coolant system.

[0035] See also Figure 1 As shown, the main body of the injection system includes the following connected in sequence:

[0036] Cooling water tank 17, used to store cooling water used for injection;

[0037] An injection pump 16, used to provide driving force for injection water;

[0038] The electric isolation valve 15 is used to isolate the injection pump 16 and to inspect and repair the injection pump 16 or to close the valve when a check valve leaks.

[0039] See also Figure 1 As shown, each main pipeline hot pipe section 3 is provided with a thermal isolation valve 8, which is used to prevent the high-temperature and high-pressure coolant of the main pipeline hot pipe section 3 from flowing to the injection system when the reactor is operating normally; each main pipeline cold pipe section 7 is provided with a cold isolation valve 9, which is used to prevent the high-temperature and high-pressure coolant of the main pipeline cold pipe section 7 from flowing to the injection system when the reactor is operating normally. All thermal isolation valves 8 and cold isolation valves 9 are connected to the electric isolation valve 15 of the injection system through the same injection system isolation valve 11; the injection system isolation valve 11 is used to play a role of re-isolation after the cold isolation valve 9 and / or the thermal isolation valve 8 fails or leaks.

[0040] See also Figure 1 As shown, the pipe section between all the hot and cold isolation valves and the injection system isolation valve 11 is defined as the 1# closed pipe section, and the pipe section between the injection system isolation valve 11 and the electric isolation valve 15 of the injection system is defined as the 2# closed pipe section. The 1# closed pipe section is provided with a first pneumatic isolation valve 13, and the 2# closed pipe section is provided with a second pneumatic isolation valve 12. The pneumatic isolation valve is used to relieve pressure in the corresponding closed pipeline in the event of overpressure; the first pneumatic isolation valve 13 and the second pneumatic isolation valve 12 are both connected to the same pressure relief box 19.

[0041] See also Figure 1 As shown, the working process of the floating reactor injection system for improving the reliability of the closed pipe section includes:

[0042] During the normal operation of the reactor, all isolation valves are closed, the medium temperature in the hot pipe section 3 of the main pipeline is as high as about 280℃ and the pressure is about 13.6MPa, the medium temperature in the cold pipe section 7 of the main pipeline is as high as about 260℃ and the pressure is about 13.6MPa, and the fluid medium in the 1# closed pipeline is in the normal temperature state of initial water filling (about 35℃) and the pressure is about 0.6MPa. Therefore, the temperature difference on both sides of the valve disc of the hot isolation valve 8 and / or the cold isolation valve 9 is large, and as the reactor continues to operate, the temperature difference always exists; when the hot isolation valve 8 and / or the cold isolation valve 9 are affected by the temperature alternation on both sides of the valve disc, and then internal leakage occurs, the high-temperature and high-pressure fluid medium in the main pipeline will flow into the 1# closed pipeline, causing the pressure of the 1# closed pipeline to increase. At this time, if the pressure reduction measures are not taken in time, it is possible that the pipeline will be damaged due to excessive pressure, so effective measures must be taken to reduce the pressure.

[0043] When the pressure of the 1# closed pipeline exceeds the specified threshold, the first pneumatic isolation valve 13 is opened to discharge the overpressure radioactive medium fluid into the pressure relief box 19 for recovery and treatment. Further, when the pressure of the 2# closed pipeline exceeds the specified threshold, it means that the hot isolation valve 8 and / or the cold isolation valve 9, as well as the injection system isolation valve 11, have failed together, that is, the high-temperature and high-pressure fluid in the 1# closed pipeline flows into the 2# closed pipeline. At this time, pressure reduction and isolation measures must be taken to prevent the radioactive medium from being further released into the cooling water tank 17. At this time, the second pneumatic isolation valve 12 is opened, and the electric isolation valve 15 is closed to discharge and isolate the radioactive medium in the 2# closed pipeline. When a loss of water accident occurs in the reactor and the injection system needs to be put into operation, it must be confirmed that the pneumatic isolation valve and the pneumatic isolation valve are in a closed state to prevent the injection water from being injected into the reactor pressure vessel 1.

[0044] It can be seen from this that when the isolation valve of the 1# closed pipeline and / or the 2# closed pipeline leaks, the present invention can promptly relieve the pressure of the closed pipe section, thereby avoiding the formation of cracks in the closed pipe section due to fatigue damage, thereby significantly improving the reliability of the closed pipe section.

[0045] Preferably, a first pressure measuring instrument 10 is provided on the 1# closed pipe section, which is used to monitor that when the pressure in the 1# closed pipe section exceeds a specified threshold, it indicates that the hot isolation valve 8 and / or the cold isolation valve 9 is leaking, and control the first pneumatic isolation valve 13 to open. A second pressure measuring instrument 14 is provided on the 2# closed pipe section; it is used to monitor that when the pressure in the 2# closed pipe section exceeds a specified threshold, it indicates that the injection system isolation valve 11 is leaking; control the electric isolation valve 15 to close to prevent the radioactive medium from entering the cooling water tank 17, and open the first pneumatic isolation valve 13 and the second pneumatic isolation valve 12 at the same time.

[0046] Preferably, the pressure relief tank 19 uses equipment for recovering and discharging radioactive media available on ships, and the reactor compartment 18 adopts a steel structure to contain high-temperature and high-pressure radioactive materials generated when an accident occurs in the reactor and the primary circuit system, and to withstand the impact of missiles.

[0047] The above are only specific implementations of the embodiments of the present invention, but the protection scope of the embodiments of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the embodiments of the present invention, and these modifications or replacements should be included in the protection scope of the embodiments of the present invention. Therefore, the protection scope of the embodiments of the present invention shall be based on the protection scope of the claims.

Claims

1. A floating reactor safety injection system for improving the reliability of a closed pipe section, comprising a reactor compartment (18) in which a safety injection system body and a reactor coolant system are arranged; characterized in that: The reactor coolant system comprises two closed loop systems, each loop system comprises a main pipeline hot pipe section (3) and a main pipeline cold pipe section (7), each main pipeline hot pipe section (3) is provided with a hot isolation valve (8), and each main pipeline cold pipe section (7) is provided with a cold isolation valve (9); all hot isolation valves (8) and cold isolation valves (9) are connected to the electric isolation valve (15) of the injection system through the same injection system isolation valve (11); the pipe section between all hot and cold isolation valves and the injection system isolation valve (11) is defined as a 1# closed pipe section, and the pipe section between the injection system isolation valve (11) and the electric isolation valve (15) of the injection system is defined as a 2# closed pipe section; a first pneumatic isolation valve (13) is provided on the 1# closed pipe section, and a second pneumatic isolation valve (12) is provided on the 2# closed pipe section; the first pneumatic isolation valve (13) and the second pneumatic isolation valve (12) are both connected to the same pressure relief box (19); The loop system specifically includes: Reactor pressure vessel (1), used to contain the reactor core assembly, ensure the integrity of the coolant pressure boundary, and prevent the release of radioactive substances into the containment vessel; A main pipeline hot pipe section (3) used to connect the outlet of the reactor pressure vessel (1) and the inlet of the steam generator (2); A steam generator (2) for removing heat generated by the reactor core; A main pipeline transition section (6) for connecting the outlet of the steam generator (2) and the inlet of the main pump (5); A main pump (5) for providing a driving pressure head for the reactor coolant; The main pipeline cold pipe section (7) is used to connect the inlet of the reactor pressure vessel (1) and the outlet of the main pump (5).

2. The floating reactor injection system for improving the reliability of the closed pipe section according to claim 1, characterized in that: A pressure stabilizer (4) is connected to the main pipeline hot pipe section (3) of any one of the loop systems, and is used to stabilize the pressure of the reactor coolant system.

3. The floating reactor injection system for improving the reliability of the closed pipe section according to claim 1, characterized in that: The main body of the injection system specifically includes the following connected in sequence: A cooling water tank (17) for storing cooling water for injection; An injection pump (16), used to provide driving force for injection water; The electric isolation valve (15) is used to isolate the injection pump (16).

4. The floating reactor injection system for improving the reliability of the closed pipe section according to claim 1, characterized in that: The 1# closed pipe section is provided with a first pressure measuring instrument (10), which is used to control the first pneumatic isolation valve (13) to open when the pressure in the 1# closed pipe section exceeds a specified threshold value; the 2# closed pipe section is provided with a second pressure measuring instrument (14), which is used to control the electric isolation valve (15) to close when the pressure in the 2# closed pipe section exceeds a specified threshold value, and simultaneously open the first pneumatic isolation valve (13) and the second pneumatic isolation valve (12).

5. The floating reactor injection system for improving the reliability of the closed pipe section according to claim 1, characterized in that: The pressure relief box (19) is selected from available equipment for recovering and discharging radioactive media.

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