Radioactive control system and method applicable to industrial steam loop of nuclear power unit

Abstract

The present invention belongs to the technical field of comprehensive utilization of nuclear energy, and specifically relates to a radioactive control system and method suitable for the industrial steam loop of a nuclear power unit. The present invention includes a reactor, a steam generator, a conventional island main engine, a condenser, a main steam fast isolation valve, an isolation valve 1, a steam energy supply fast isolation valve, a steam-steam heat exchange device, a desalted water supply system, and a regulating valve isolation valve 2. The present invention can prevent radioactive nuclides from migrating from a nuclear power plant to a seawater desalination device or a regional centralized heating device under the operating state and accident conditions of a nuclear power plant providing industrial steam, thereby ensuring the radiation safety of the staff in the plant, the steam users outside the plant, and the environment.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive utilization of nuclear energy, and in particular relates to a radioactive control system and method suitable for an industrial steam loop of a nuclear power unit. Background Art

[0002] The technical safety and reliability of nuclear power units have been fully verified. At present, nuclear power units in China are mainly used for power generation, and they also provide a small amount of hot water to urban hot water pipe networks for heating. However, there is no precedent for nuclear power units in the field of industrial steam supply.

[0003] Conventional cogeneration has been successful in thermal power units, but considering the particularity of nuclear power units, nuclear power units cannot directly use secondary circuit steam as industrial steam. It is necessary to consider controlling the radioactivity of industrial steam production and make technological innovations in control methods and systems to ensure that the radioactivity control of industrial steam produced by nuclear power units is safe and reliable. Therefore, it is necessary to explore a radioactivity control system for nuclear power units that use nuclear energy to produce industrial steam to ensure the radiation safety of steam users. Summary of the invention

[0004] The object of the present invention is to provide a radioactivity control system and method suitable for an industrial steam loop of a nuclear power unit, which can prevent radioactive nuclides from migrating from a nuclear power plant to a seawater desalination device or a regional central heating device under the operating state and accident conditions of a nuclear power plant providing industrial steam, thereby ensuring the radiation safety of plant workers, steam users outside the plant and the environment.

[0005] The technical solution adopted by the present invention is:

[0006] A radioactive control system suitable for the industrial steam loop of a nuclear power unit, comprising a reactor, a steam generator, a conventional island main engine, a condenser, a main steam fast isolation valve, an isolation valve 1, a steam energy supply fast isolation valve, a steam-steam heat exchange device, a desalted water supply system, and a regulating valve isolation valve 2; the reactor is connected to the bottom of the steam generator, the top of the steam generator is connected to the conventional island main engine, and is connected to the steam-steam heat exchange device through a main steam pipeline, the conventional island main engine is connected to the steam generator through a condenser, the steam-steam heat exchange device is connected to the condenser, and the heat energy generated in the reactor is carried away by the coolant In the steam generator, secondary circuit main steam is produced through heat exchange. Part of the main steam is circulated through the conventional island main engine and condenser, and part of it is passed through the modified pipeline and successively passes through the main steam fast isolation valve, isolation valve 1, and steam supply fast isolation valve to enter the steam-steam heat exchange equipment. After passing through the steam-steam heat exchange equipment, the main steam is converted into condensate and returns to the condenser; in the steam-steam heat exchange equipment, the steam-steam heat exchange equipment is connected to the desalted water system, and the desalted water produced by the desalted water system is heated into industrial steam, which is transported to industrial users outside the factory through pipelines. A regulating valve and an isolation valve 2 are provided on the pipeline in sequence.

[0007] The steam generator is provided with a leakage monitoring system. The steam generator is connected to the gamma sampling monitoring system 1 through sampling valve 1 and the sampling valve 2 is connected to the nuclear island floor drain system. The radioactivity in the steam generator is sampled and monitored through the nuclear island floor drain system.

[0008] The gamma sampling monitoring system 1 is a regular monitoring system, which samples and monitors once a week.

[0009] The main steam pipeline is provided with N 16 Activity detector, and gamma detector 1, gamma detector 2, gamma detector 3, gamma detector 4. If a leak occurs on the steam generator side, the radioactive material leaks to the main steam gamma dose rate through 4 gamma detectors. The 4 gamma detectors use the principle of 2 out of 4 to trigger the interlocking closing signal of the main steam fast isolation valve and the steam energy fast isolation valve; N 16 The activity detector measures the leakage rate and triggers the interlocking closing signal of the steam supply fast isolation valve according to the leakage rate limit to ensure that radioactive steam does not enter the steam-steam heat exchange equipment.

[0010] The steam-steam heat exchange equipment is connected to the wastewater collection system through sampling valve 3, gamma sampling monitoring system 2, and sampling valve 4. The gamma sampling monitoring system 2 samples and monitors the radioactivity of the steam-steam heat exchange equipment. The gamma sampling monitoring system 2 is a regular monitoring system that samples and monitors weekly, and when the gamma sampling monitoring system 1, gamma detector 1, gamma detector 2, gamma detector 3, gamma detector 4 or N 16 When an alarm signal appears in the activity detector, sampling monitoring is carried out.

[0011] The industrial steam pipeline after the regulating valve is connected to the wastewater collection system through sampling valve five, gamma online monitoring system one and sampling valve six. The pipeline steam is condensed in the gamma online monitoring system and the radioactivity is monitored. After the system is put into operation, the system is a real-time monitoring system.

[0012] The industrial steam pipeline is provided with a gamma detector five to monitor the radioactive activity on the industrial steam side in real time, the gamma online monitoring system, the monitoring signals of the gamma detector five, and the monitoring data are fed back to the industrial steam users, the main instrumentation and control system and the environmental supervision department in real time, and are interlocked with the control signal of the isolation valve two.

[0013] A radioactivity control method applicable to an industrial steam loop of a nuclear power plant comprises the following steps:

[0014] Step 1: When the leakage of a single steam generator exceeds 4.0 kg / h, N 16 The activity detector gives priority to sending out a chain control signal to close the steam energy supply quick isolation valve to protect the shut-down steam energy supply device and prevent radioactive substances from entering the steam-steam heat exchanger and downstream;

[0015] Step 2: When the γ radioactivity is greater than 1×10 6 Gy / h, 4 gamma detectors use the principle of 2 out of 4 to trigger the interlocking control signal to close the steam energy supply fast isolation valve, protect the shut-down steam energy supply device, and prevent radioactive substances from entering the steam-steam heat exchanger and downstream;

[0016] Step 3: When the γ radioactivity is greater than 2×10 6 Gy / h, the steam energy supply device is shut down by taking a signal from the reactor protection system. This signal is a safety-level signal, which interlocks and closes the steam energy supply fast isolation valve to protect the shut-down steam energy supply device and prevent radioactive substances from entering the steam-steam heat exchanger and downstream;

[0017] Step 4. When an unexpected accident occurs during the closing process of step 3, the isolation valve 1 is remotely closed by the main control to cut off the pipeline leading to the steam-steam heat exchange equipment with radioactive substances. While the isolation valve 1 is remotely closed, the radioactivity monitoring data of the gamma online monitoring system and the gamma detector 5 are read in real time to determine whether the radioactivity has leaked to the steam-steam heat exchange equipment and its downstream pipeline.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The present invention provides a radioactivity control system and method applicable to the industrial steam loop of a nuclear power unit. The secondary loop of a nuclear power plant is used as an intermediate isolation loop between the reactor main coolant loop and the industrial steam loop to effectively prevent the secondary loop medium with potential radioactivity from migrating to the industrial steam side. By real-time monitoring of the radioactivity concentration of the secondary loop, the valve status of the steam supply pipeline is controlled to ensure that the industrial steam loop medium is not contaminated by radioactivity. At the same time, a radioactivity monitoring instrument is installed in the industrial steam loop to monitor the industrial steam pipeline in real time to ensure that the industrial steam side is always free of radioactivity.

[0020] (2) The present invention provides a radioactivity control system and method applicable to the industrial steam loop of a nuclear power unit, wherein a steam-to-steam heat exchange device is provided to form a new isolation loop, which can prevent the secondary loop medium with potential radioactivity from migrating to the industrial steam loop under normal operating conditions.

[0021] (3) The present invention provides a radioactivity control system and method applicable to the industrial steam loop of a nuclear power unit. A quick isolation valve is set before the steam-steam heat exchanger. In the event of a radioactivity leakage event, the steam energy quick isolation valve is closed to prevent potential radioactivity from entering the steam-steam equipment and downstream pipelines. A total of 4 shutdown signal barriers are set to ensure effective isolation.

[0022] (4) The present invention provides a radioactive control system and method applicable to the industrial steam loop of a nuclear power unit, which is provided with four gamma detectors. The four detectors use a 2-out-of-4 control logic to set the threshold value and interlock with the rapid isolation valve control signal, and send out an interlocking signal to close the rapid isolation valve.

[0023] (5) The present invention provides a radioactive control system and method applicable to the industrial steam loop of a nuclear power plant, which is provided with N -16 Activity detector detects the leakage rate of the evaporator heat transfer tube, sets the threshold and interlocks with the quick isolation valve control signal. When the threshold is exceeded, a interlocking signal is sent to close the quick isolation valve.

[0024] (6) The present invention provides a radioactive control system and method applicable to the industrial steam circuit of a nuclear power unit, which is provided with a gamma sampling monitoring system. When a small leak occurs in the evaporator, the radioactive -16 When the activity detector and gamma detector are offline, regular sampling and analysis are performed to determine whether there are any small leaks.

[0025] (7) The present invention provides a radioactive control system and method suitable for an industrial steam loop of a nuclear power unit. The steam power supply fast isolation valve is of nuclear safety grade and can be closed by controlling the reactor shutdown protection signal as a safety grade closing signal of the steam power supply fast isolation valve.

[0026] (8) The present invention provides a radioactivity control system and method applicable to the industrial steam circuit of a nuclear power unit, wherein the installation position, valve closing time, and characteristic curve of the steam energy supply rapid isolation valve are accurately calculated. Based on the time T1 from the occurrence of an accident to reaching the radioactivity threshold, the instrumentation and control system reaction time T2, and the valve closing time T3, the distance that the steam is transmitted within the total time of T1+T2+T3 is less than the installation distance from the steam generator to the rapid isolation valve.

[0027] (9) The present invention provides a radioactive control system and method applicable to the industrial steam loop of a nuclear power plant, which is equipped with a gamma detector and a gamma online monitoring system to monitor the radioactive data of the industrial steam loop in real time. The data is not linked to the control system and is fed back to the steam user, environmental monitoring system, etc. to prove the radioactive safety of the system.

[0028] (10) The present invention provides a radioactive control system and method suitable for an industrial steam loop of a nuclear power unit. The steam-to-steam equipment is provided with a gamma sampling monitoring system, which performs sampling and analysis by periodic sampling or when other signals generate an alarm, thereby avoiding minor leakage conditions and confirming false triggering of signals.

[0029] (11) The present invention provides a radioactive control system and method suitable for the industrial steam loop of a nuclear power unit. The system is provided with a plant outlet isolation valve, which is used for maintenance isolation under normal operating conditions. When an alarm is generated in the real-time monitoring system on the industrial steam side of the steam-to-steam equipment outlet, the valve is remotely closed to control the potential radioactive conditions within the plant area. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention provides a schematic diagram of the structure of a radioactive control system applicable to an industrial steam loop of a nuclear power plant;

[0031] In the figure: 1-reactor, 2-steam generator, 3-conventional island main engine, 4-condenser, 5-sampling valve 1, 6-gamma sampling monitoring system 1, 7-sampling valve 2, 8-nuclear island floor drain system, 9-N -16 Activity detector, 10-Gamma detector one, 11-Gamma detector two, 12-Gamma detector three, 13-Gamma detector four, 14-Main steam fast isolation valve, 15-Issulation valve one, 16-Steam energy supply fast isolation valve, 17-Steam-steam heat exchange equipment, 18-Desalted water supply system, 19-Sampling valve three, 20-Gamma sampling monitoring system two, 21-Sampling valve four, 22-Wastewater collection system, 23-Regulating valve, 24-Sampling valve five, 25-Gamma online monitoring system, 26-Sampling valve six, 27-Gamma detector five, 28-Issulation valve two. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the 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 orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0034] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] A radioactivity control system suitable for an industrial steam loop of a nuclear power unit is provided with a nuclear power unit steam generator leakage rate monitoring, a steam generator main steam pipeline radioactivity monitoring, and a multi-stage rapid isolation valve, and the radioactivity monitoring signal, the leakage rate monitoring signal and the nuclear-grade rapid isolation valve switch control signal are interlocked. When a radioactivity leak occurs in the steam generator, the radioactivity monitoring signal can be used to trigger the control signal of the rapid isolation valve, and the safety-level valve on the pipeline can be closed in time to ensure that radioactive substances will not leak into a steam-steam heat exchanger 17 and downstream steam pipelines and users.

[0036] The system mainly includes a reactor 1, a steam generator 2, a conventional island host 3, a condenser 4, a sampling valve 1 5, a gamma sampling monitoring system 1 6, a sampling valve 2 7, a nuclear island floor drain system 8, and a N 16 Activity detector 9, gamma detector one 10, gamma detector two 11, gamma detector three 12, gamma detector four 13, main steam fast isolation valve 14, isolation valve one 15, steam energy supply fast isolation valve 16, steam-steam heat exchange equipment 17, desalted water supply system 18, sampling valve three 19, gamma sampling monitoring system two 20, sampling valve four 21, wastewater collection system 22, regulating valve 23, sampling valve five 24, gamma online monitoring system 25, sampling valve six 26, gamma detector five 27, isolation valve two 28.

[0037] The reactor 1 is connected to the bottom of the steam generator 2, and the top of the steam generator 2 is connected to the conventional island main engine 3, and is connected to the steam-steam heat exchange equipment 17 through the main steam pipeline. The conventional island main engine 3 is connected to the steam generator 2 through the condenser 4, and the steam-steam heat exchange equipment 17 is connected to the condenser 4. The heat energy generated in the reactor 1 is brought to the steam generator 2 by the coolant, and the secondary circuit main steam is produced through heat exchange. A part of the main steam forms a cycle through the conventional island main engine 3 and the condenser 4, and a part of the main steam passes through the main steam fast isolation valve 14, the isolation valve 15, and the steam energy supply fast isolation valve 16 through the modified pipeline to enter the steam-steam heat exchange equipment 17. After the main steam passes through the steam-steam heat exchange equipment 17, it becomes condensate and returns to the condenser 4; in the steam-steam heat exchange equipment 17, the steam-steam heat exchange equipment 17 is connected to the desalted water system 18, and the desalted water generated by the desalted water system 18 is heated into industrial steam, which is transported to industrial users outside the plant through the pipeline. The pipeline is provided with a regulating valve 23 and an isolation valve 28 in sequence.

[0038] A leakage monitoring system is provided in the steam generator 2. The steam generator 2 is connected to the gamma sampling monitoring system 16 through a sampling valve 15 and to the nuclear island floor drain system 8 through a sampling valve 27. The radioactivity in the steam generator 2 is sampled and monitored through the nuclear island floor drain system 8. The gamma sampling monitoring system 16 is a regular monitoring system, and sampling and monitoring are performed once a week.

[0039] On the main steam line, N 16 Activity detector 9, and gamma detector one 10, gamma detector two 11, gamma detector three 12, gamma detector four 13, if leakage occurs on the steam generator side, the radioactive material leaks to the extent that the main steam gamma dose rate can be monitored by four gamma detectors, and the four gamma detectors can trigger the main steam fast isolation valve 14 and the steam energy supply fast isolation valve 16 interlocking closing signals based on the principle of 2 out of 4; N 16 The activity detector 9 can measure the leakage rate and trigger the interlocking closing signal of the steam-powered rapid isolation valve 16 according to the leakage rate limit to ensure that the radioactive steam does not enter the steam-steam heat exchange equipment 17.

[0040] The steam-steam heat exchange equipment 17 is connected to the wastewater collection system 22 through the sampling valve three 19, the gamma sampling monitoring system two 20, and the sampling valve four 21. The gamma sampling monitoring system two 20 samples and monitors the radioactivity of the steam-steam heat exchange equipment 17. The gamma sampling monitoring system two 20 is a regular monitoring system, which samples and monitors every week, and when the gamma sampling monitoring system one 6, the gamma detector one 10, the gamma detector two 11, the gamma detector three 12, the gamma detector four 13 or N 16 When an alarm signal appears in the activity detector 9, sampling monitoring is carried out.

[0041] The industrial steam pipeline after the regulating valve 23 is connected to the wastewater collection system 22 through the sampling valve five 24, the gamma online monitoring system one 25 and the sampling valve six 26. The pipeline steam is condensed in the gamma online monitoring system 25 and the radioactivity is monitored. After the system is put into operation, the system is a real-time monitoring system; a gamma detector five 27 is arranged on the industrial steam pipeline to monitor the radioactive activity on the industrial steam side in real time, the monitoring signals of the gamma online monitoring system 25 and the gamma detector five 27, and the monitoring data are fed back to the industrial steam users, the main instrumentation and control system and the environmental supervision department in real time, and are interlocked with the control signal of the isolation valve two 28. When an alarm occurs, the isolation valve two 8 is closed.

[0042] The entire system is divided into normal operating conditions and accident conditions. Since the protection signals at all levels take safety margins into account, when an accident condition occurs, if the upstream radioactivity control measures fail, downstream measures will continue to be invested to ensure the radioactivity safety of industrial steam.

[0043] Its main working conditions are as follows:

[0044] 1. Normal operating conditions

[0045] Under normal operating conditions, sampling valve 1 5, sampling valve 2 7, sampling valve 3 19, sampling valve 4 21 are closed, gamma online monitoring system 25, gamma detector 5 27, N 16 Activity detector 9, gamma detector 1 10, gamma detector 2 11, gamma detector 3 12 and gamma detector 4 13 are put into operation, and other valves are in the open state to monitor the radioactive parameters in the system. At this time, the secondary circuit main steam serves as the intermediate isolation circuit between the reactor main coolant circuit and the industrial steam circuit, effectively preventing the secondary circuit medium with potential radioactivity from migrating to the industrial steam side.

[0046] 2. Steam supply rapid isolation valve control under accident conditions

[0047] According to the characteristics of the steam energy supply system and the requirements for the radioactivity of industrial steam, the energy supply system is equipped with a nuclear three-level steam energy supply fast isolation valve 16 to control the external diffusion of radioactivity. When the radioactivity reaches the action limit, the radioactivity monitoring signal is linked to the valve through the nuclear island protection system to quickly close the steam energy supply system, and the steam supply of the unit to the energy supply system is promptly cut off to ensure that the radioactivity in the industrial steam meets the safety margin requirements. The valve is a two-safety-level solenoid valve with redundant safety channels. Each channel accepts safety-level and non-safety-level commands. When any channel receives a valve closing command, the valve will close. The valve is a pneumatic valve, and the valve remains closed when the valve loses power and air.

[0048] In the event of leakage from the primary circuit to the secondary circuit, in order to ensure the timely and reliable operation of the steam energy supply device, the following multiple signals are used to ensure the reliable operation of the steam energy supply fast isolation valve, mainly including:

[0049] (1) When the leakage of a single steam generator exceeds 4.0 kg / h, N 16 The activity detector 9 gives priority to sending out a chain control signal to close the steam energy supply quick isolation valve 16 to protect the steam energy supply device from being shut down and to prevent radioactive substances from entering the steam-steam heat exchanger 17 and downstream;

[0050] (2) When the γ-radioactivity is greater than 1×10 6 Gy / h, 4 gamma detectors (gamma detector 1 10, gamma detector 2 11, gamma detector 3 12, gamma detector 4 13) use the principle of 2 out of 4 to trigger the interlocking control signal to close the steam supply fast isolation valve 16, protect the steam supply energy device that is out of service, and prevent radioactive substances from entering the steam-steam heat exchanger 17 and downstream. This signal is delayed compared to the reaction time of (1) and is the safety margin signal of (1). When N 16 When the activity detector 9 fails, this signal can effectively ensure that radioactive materials do not enter the steam-steam heat exchanger 17 and downstream;

[0051] (3) When the γ-radioactivity is greater than 2×10 6 Gy / h, the steam energy supply device is shut down by taking a signal from the reactor protection system. This signal is a safety-level signal. This signal is interlocked to close the steam energy supply fast isolation valve 16 to protect the shut-down steam energy supply device and prevent radioactive substances from entering the steam-steam heat exchanger 17 and downstream; (3) is the third barrier after (1) and (2). When both (1) and (2) are breached, (3) can effectively close the steam energy supply fast isolation valve 16. At this time, the valve closing time satisfies T1+T2+T3≤18 seconds. This time calculation takes the VVER unit as an example: in the accident condition, the transmission time of the main steam containing radioactivity from the heat transfer pipe to the steam generator outlet is 2s, the transmission time of the main steam from the steam generator outlet to the conventional island main steam connecting main pipe is 2.25s, and the time for the main steam to reach the steam energy supply fast isolation valve from the conventional island connecting main pipe through the plant area steam pipeline is 13.75s. Therefore, in the event of an accident, the time required for the main steam containing radioactive substances to be transferred from the steam generator to the steam energy supply rapid isolation valve is greater than or equal to 18 seconds. Closing the steam energy supply rapid isolation valve 16 within 18 seconds can effectively prevent the leakage of radioactive substances to the steam-steam heat exchange equipment 17.

[0052] (4) When an unexpected accident occurs during the shutdown process (3), such as a failure of the steam energy supply rapid isolation valve 16, the isolation valve 15 can be remotely closed by the master control to cut off the pipeline of radioactive materials to the steam-to-steam heat exchange equipment 17. Since the closing time is unpredictable at this time, when the isolation valve 15 is remotely closed, the radioactive monitoring data of the gamma online monitoring system 25 and the gamma detector 5 27 can be read in real time to determine whether the radioactivity has leaked to the steam-to-steam heat exchange equipment 17 and its downstream pipeline. The isolation valve 2 28 can be remotely closed to further ensure that the radioactive materials are controlled within the nuclear power plant area, effectively preventing the industrial steam from containing radioactive materials.

[0053] As can be seen from the above, the present invention provides a radioactive control system for the industrial steam loop of a nuclear power unit. The system has a high safety margin and a multi-barrier design, which can effectively control the radioactive leakage risk link of nuclear energy production of industrial steam and has high reliability. It provides a new solution for radioactive control in the field of comprehensive utilization of nuclear energy.

[0054] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0055] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A radioactivity control system suitable for an industrial steam loop of a nuclear power plant, characterized in that: The invention comprises a reactor (1), a steam generator (2), a conventional island main engine (3), a condenser (4), a main steam rapid isolation valve (14), an isolation valve 1 (15), a steam energy supply rapid isolation valve (16), a steam-steam heat exchange device (17), a desalted water supply system (18), a regulating valve (23) and an isolation valve 2 (28); the reactor (1) is connected to the bottom of the steam generator (2), the top of the steam generator (2) is connected to the conventional island main engine (3), and is connected to the steam-steam heat exchange device (17) through a main steam pipeline, the conventional island main engine (3) is connected to the steam generator (2) through the condenser (4), the steam-steam heat exchange device (17) is connected to the condenser (4), and the heat energy generated in the reactor (1) is carried to the steam generator (2) by the coolant. In the steam generator (2), secondary circuit main steam is produced through heat exchange. A part of the main steam is circulated through the conventional island main engine (3) and the condenser (4), and a part of the main steam is passed through the modified pipeline and successively passes through the main steam fast isolation valve (14), the isolation valve 1 (15), and the steam energy supply fast isolation valve (16) to enter the steam-steam heat exchange device (17). After passing through the steam-steam heat exchange device (17), the main steam is converted into condensate and returns to the condenser (4); in the steam-steam heat exchange device (17), the steam-steam heat exchange device (17) is connected to the desalted water system (18), and the desalted water generated by the desalted water system (18) is heated into industrial steam, which is transported to industrial users outside the factory through pipelines. The pipelines are provided with regulating valves (23) and isolation valve 2 (28) in sequence.

2. A radioactivity control system suitable for an industrial steam loop of a nuclear power plant according to claim 1, characterized in that: The steam generator (2) is provided with a leakage monitoring system. The steam generator (2) is connected to a gamma sampling monitoring system (6) via a sampling valve (5) and a sampling valve (7) is connected to a nuclear island floor drain system (8). The radioactivity in the steam generator (2) is sampled and monitored via the nuclear island floor drain system (8).

3. A radioactivity control system suitable for an industrial steam loop of a nuclear power plant according to claim 2, characterized in that: The gamma sampling monitoring system 1 (6) is a regular monitoring system, which performs sampling and monitoring once a week.

4. A radioactivity control system suitable for an industrial steam loop of a nuclear power plant according to claim 3, characterized in that: The main steam pipeline is provided with N 16 Activity detector (9), and gamma detector 1 (10), gamma detector 2 (11), gamma detector 3 (12), gamma detector 4 (13), if leakage occurs on the steam generator side, radioactive substances leak to the main steam gamma dose rate through the four gamma detectors, the four gamma detectors use the principle of 2 out of 4 to trigger the main steam fast isolation valve (14), steam energy fast isolation valve (16) interlocking closing signal; N 16 The activity detector (9) measures the leakage rate and triggers the interlocking closing signal of the steam-powered rapid isolation valve (16) according to the leakage rate limit value, so as to ensure that the steam containing radioactivity does not enter the steam-steam heat exchange equipment (17).

5. A radioactivity control system suitable for an industrial steam loop of a nuclear power plant according to claim 4, characterized in that: The steam-steam heat exchange device (17) is connected to the wastewater collection system (22) via a sampling valve three (19), a gamma sampling monitoring system two (20), and a sampling valve four (21). The gamma sampling monitoring system two (20) performs sampling monitoring on the radioactivity of the steam-steam heat exchange device (17). The gamma sampling monitoring system two (20) is a regular monitoring system that performs sampling monitoring every week, and when the gamma sampling monitoring system one (6), the gamma detector one (10), the gamma detector two (11), the gamma detector three (12), the gamma detector four (13), or N 16 When an alarm signal appears in the activity detector (9), sampling monitoring is carried out.

6. A radioactivity control system suitable for an industrial steam loop of a nuclear power plant according to claim 5, characterized in that: The industrial steam pipeline after the regulating valve (23) is connected to the wastewater collection system (22) through the sampling valve five (24), the gamma online monitoring system (25), and the sampling valve six (26). The pipeline steam is condensed in the gamma online monitoring system (25) and the radioactivity is monitored. After the system is put into operation, the system is a real-time monitoring system.

7. A radioactivity control system suitable for an industrial steam loop of a nuclear power plant according to claim 6, characterized in that: The industrial steam pipeline is provided with a gamma detector five (27) to monitor the radioactivity on the industrial steam side in real time. The gamma online monitoring system (25) and the monitoring signals of the gamma detector five (27) are fed back to the industrial steam user, the main instrumentation and control system and the environmental supervision department in real time, and are interlocked with the control signal of the isolation valve two (28).

8. A radioactivity control method applicable to an industrial steam loop of a nuclear power plant, based on the radioactivity control system applicable to an industrial steam loop of a nuclear power plant as claimed in claim 7, characterized in that: The steps include: Step 1: When the leakage of a single steam generator exceeds 4.0 kg / h, N 16 The activity detector (9) gives priority to sending a chain control signal to close the steam energy supply quick isolation valve (16) to protect the steam energy supply device from being shut down and prevent radioactive substances from entering the steam-steam heat exchanger (17) and downstream; Step 2: When the γ radioactivity is greater than 1×10 6 Gy / h, four gamma detectors use the principle of 2 out of 4 to trigger a chain control signal to close the steam energy supply quick isolation valve (16), protect the steam energy supply device that is out of service, and prevent radioactive substances from entering the steam-steam heat exchanger (17) and downstream; Step 3: When the γ radioactivity is greater than 2×10 6 Gy / h, the steam energy supply device is shut down by taking a signal from the reactor protection system. This signal is a safety-level signal, which interlocks and closes the steam energy supply fast isolation valve (16) to protect the shut-down steam energy supply device and prevent radioactive substances from entering the steam-steam heat exchanger (17) and downstream; Step 4: When an unexpected accident occurs during the closing process of step 3, the isolation valve 1 (15) is remotely closed by the main control to cut off the pipeline leading to the steam-steam heat exchange device (17). While the isolation valve 1 (15) is remotely closed, the radioactivity monitoring data of the gamma online monitoring system (25) and the gamma detector 5 (27) are read in real time to determine whether the radioactivity has leaked to the steam-steam heat exchange device (17) and its downstream pipeline.

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