Radiation monitoring method and monitoring system for external supply of industrial steam in nuclear power plant
By installing gamma-ray radiation detection sensors on the steam generator pipelines of nuclear power plants, leak points can be monitored and sealed, thus solving the problem of radiation leakage during the industrial steam supply process of nuclear power plants and achieving effective radiation monitoring and safety protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGXI FANGCHENGGANG NUCLEAR POWER
- Filing Date
- 2026-01-09
- Publication Date
- 2026-04-10
AI Technical Summary
In the process of supplying industrial steam, nuclear power plants have a multi-level isolation structure that results in numerous pipelines, making it difficult to effectively monitor radiation leaks and posing a risk that radioactive nuclides may leave the plant through external steam supply pipelines.
Several steam radioactivity detection sensors are installed on the main steam pipeline, sewage pipeline, and external industrial steam supply pipeline of the steam generator. Leakage is monitored by detecting gamma radioactivity activity, and alarms are triggered and corresponding pipelines are shut down at different safety values to seal the leak point.
It enables comprehensive leakage monitoring of the secondary and tertiary heat exchange pipelines of nuclear power plants, timely prevents radionuclides from leaving the plant through external steam pipelines, and ensures nuclear safety.
Smart Images
Figure CN121831850A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of nuclear power plant detection, and in particular to a radiation monitoring method and system for industrial steam supplied by a nuclear power plant. Background Technology
[0002] Nuclear power, as a clean energy source, plays a significant role in reducing carbon dioxide emissions, mitigating pollutant emissions, improving environmental quality, and lowering PM2.5 concentrations by developing nuclear power as a substitute for fossil fuels. Pressurized water reactor nuclear power plants supply industrial steam through a "steam conversion" process. This involves using steam generated in the secondary loop of the nuclear power unit as a heat source, transferring heat to an independent industrial steam loop through a multi-stage physically isolated heat exchange system, and ultimately generating industrial-standard steam for delivery to users. This method retains the core function of nuclear power generation while achieving efficient energy utilization through "combined heat and power" (CHP). It also ensures nuclear safety through multi-stage isolation design. However, the multi-stage isolation structure results in numerous pipelines, necessitating a system and method for monitoring pipeline radiation leaks. Summary of the Invention
[0003] The technical problem to be solved by the present invention is to provide a radiation monitoring method and system for industrial steam supplied by a nuclear power plant.
[0004] The technical solution adopted by this invention to solve its technical problem is as follows: A radiation monitoring system for the external supply of industrial steam from a nuclear power plant is constructed, comprising: a reactor, a steam generator connected to the reactor via a pipeline, the steam generator having a main steam pipeline and a wastewater pipeline, a steam reheater connected to the steam generator via the main steam pipeline, an external industrial steam pipeline for external steam supply on the steam reheater, a first sensor group for detecting the gamma radioactivity of the steam on the main steam pipeline, a second sensor group for detecting the gamma radioactivity of the steam on the wastewater pipeline, a third sensor group for detecting the gamma radioactivity of the steam on the external industrial steam pipeline, a first switching valve on the main steam pipeline, a second switching valve on the wastewater pipeline, and a third switching valve on the external industrial steam pipeline.
[0005] Furthermore, the first sensor group, the second sensor group, and the third sensor group are several steam radioactivity detection sensors. The four steam radioactivity detection sensors are evenly distributed around the pipe, with four in a circle forming a set, and two sets forming a sensor group.
[0006] The technical solution adopted by this invention to solve its technical problem is: to construct a radiation monitoring method for industrial steam supplied by a nuclear power plant, comprising the following steps: Step S1: Collect historical leak records and leak severity of the main steam pipe, the drain pipe of the steam generator, and the external industrial steam supply pipe of the steam generator. Step S2: Based on historical leakage records and the severity of the leakage, select corresponding monitoring points on the main steam pipeline of the steam generator, the drain pipeline of the steam reheater, and the external industrial steam supply pipeline of the steam reheater. Step S3: Place several sets of steam radioactivity detection sensors on the main steam pipe of the steam generator, the sewage pipe of the steam generator, and the monitoring point on the external industrial steam supply pipe. The sensors set on the main steam pipe are the first sensor set and the second sensor set, and the sensors set on the external industrial steam supply pipe are the third sensor set. Step S4: When the first sensor group, the second sensor group, and the third sensor group detect that the γ radioactivity activity is greater than the first safety value, a first alarm signal is issued. Step S5: When the manager receives the first alarm, he opens the pipeline to take liquid samples at the location where the first alarm signal was issued, and performs gamma radioactivity detection again. If the gamma radioactivity detection value is greater than the first safety value again, the leaking steam generator is identified, the leak point is investigated, and the leak point is sealed. Step S6: When the first sensor group, the second sensor group, and the third sensor group detect that the γ radioactivity activity is greater than the second safety value, a second alarm signal is issued. Step S7: Identify the pipe where the steam generator is leaking, locate the leak point, shut off the steam supply pipe and the drain pipe of the steam generator, and seal the leak point.
[0007] Furthermore, the first safety value for the first sensor group is 4 × 10⁻⁶. 4 Bq / m 3 The first safety value for the second sensor group is 9×10. 5 Bq / m 3 The first safety value of the third sensor group is 3×10. 3 Bq / m 3 .
[0008] Furthermore, the second safety value for the first sensor group is 4 × 10⁻⁶. 6 Bq / m 3 The second safety value for the second sensor group is 9×10. 7 Bq / m 3 The second safety value of the third sensor group is 3×10. 4 Bq / m 3 .
[0009] Further, in steps S2 and S4, the first sensor group needs to detect the steam leakage rate. The steam leakage rate is calculated based on the gamma radioactivity and the following formula: ; In the formula, q is the steam leakage rate, with units of kg·s. -1 n is 16 The gamma radioactivity of N, measured in s. -1 Q v Steam flow rate, unit: kg·s -1 ;ρ P Main loop water density, kg·m -3 Q P Main loop water flow rate, kg·s -1 Q P Branch loop water flow rate, kg·s -1 λ is the decay constant, s -1 T represents the main loop water circulation cycle in seconds (s); L1 represents the length of the pipe from the reactor active zone outlet to the hot end of the steam generator in meters (m); S1 represents the main loop pipe area in square meters (m²); m represents the number of heat transfer tubes in the steam generator; L2 represents the pipe length from the hot end of the steam generator to the point of damage to the heat transfer tube in meters (m); S2 represents the cross-sectional area of the heat transfer tube in square meters (m²). 2 L3 is the pipe length from the steam outlet of the steam generator to the detector, in meters (m); S3 is the cross-sectional area of the steam pipe, in square meters (m²). 2 ;ρ v This refers to the density of steam, expressed in kg·m³. -3 Q v Steam flow rate, unit: kg·s -1 t1 is the time it takes for the main loop water to pass through the reactor active zone, in seconds; t2 is... 16 N is the diffusion time from the point of failure in the self-heating pipe to the steam outlet of the steam generator, measured in seconds; k is the diffusion time of the detector in the main steam pipe. 16 The detection efficiency of N, where N is the nuclear density of the water in the main loop of the reactor core, in kg. -1 σ(E) is the reaction cross-sectional area at neutron energy E, in m². 2 φn(E)dE represents the neutron flux rate in the reactor active region, from energy E to E+d, in m³ / s. -2 ·s -1 Eth neutron threshold energy, in MeV.
[0010] Furthermore, in steps S2 and S4, when the first safe value of the first steam leakage rate of the first sensor group is greater than 4 L / h, a first alarm signal is issued; when the first safe value of the first steam leakage rate detected by the first sensor is greater than 70 L / h, a second alarm signal is issued.
[0011] Furthermore, in step S5, when the manager receives the second alarm signal from the first sensor group and the second sensor group, if the leak point cannot be detected after 24 hours of investigation, the unit needs to be withdrawn to the hot shutdown condition. The withdrawal of the unit to the hot shutdown condition is the operation process of the nuclear power unit transitioning from normal operation to short-term shutdown.
[0012] Furthermore, in step S3, when the first alarm signal is received, the wastewater from the steam generator's drain pipe is switched to the nuclear island waste liquid treatment channel.
[0013] Furthermore, in step S2, if there has been no previous record of leakage, a monitoring point is set within 2-4 meters of the main steam pipeline near the steam generator, a monitoring point is set within 2-4 meters of the sewage pipeline near the steam reheater, and a monitoring point is set within 2-4 meters of the external industrial steam pipeline near the steam reheater.
[0014] The radiation monitoring method for industrial steam supplied by a nuclear power plant according to the present invention has the following beneficial effects: Several steam radioactivity detection sensors are installed on the main steam pipeline, sewage pipeline and external industrial steam supply pipeline of the steam generator to detect leaks in the main steam pipeline, sewage pipeline and external industrial steam supply pipeline. When the leakage exceeds the first safety value, personnel are arranged to conduct a re-inspection. If it is found that it still exceeds the first safety value, leakage investigation is carried out. When the leakage exceeds the second safety value, the main steam pipeline and sewage pipeline of the steam generator are shut down and the leak point is detected immediately. This method can timely, effectively and reliably prevent radioactive nuclides leaking into the secondary coolant under abnormal operating conditions from leaving the plant through the external steam supply pipeline.
[0015] The radiation monitoring system for nuclear power plants supplying industrial steam according to this invention has the following beneficial effects: By installing several steam radioactivity detection sensors on the main steam pipeline, sewage pipeline, and external industrial steam pipeline of the steam generator, leaks in the main steam pipeline, sewage pipeline, and external industrial steam pipeline are detected, and comprehensive leak monitoring is carried out on the pipelines of the secondary and tertiary heat exchange circuits of the nuclear power plant, effectively preventing radioactive nuclides from leaving the plant through the external steam pipeline. Attached Figure Description
[0016] To more clearly illustrate the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort. In the drawings: Figure 1 This is an overall structural diagram of a radiation monitoring system for industrial steam supplied by a nuclear power plant in one embodiment of the present invention; Figure 2 This is a sensor layout diagram of a radiation monitoring method for industrial steam supplied by a nuclear power plant in one embodiment of the present invention. Figure 3 This is a flowchart of a radiation monitoring method for industrial steam supplied by a nuclear power plant in one embodiment of the present invention; Figure 4 This is a logic diagram of a radiation monitoring method for industrial steam supplied by a nuclear power plant in one embodiment of the present invention.
[0017] Reference signs 100. Reactor; 110. Steam generator; 111. Main steam pipeline; 120. Steam reheater; 121. External industrial steam pipeline; 131. Sewage pipeline; 200. First sensor group; 210. Second sensor group; 220. Third sensor group; 300. First switching valve; 310. Second sensor; 320. Third sensor. Detailed Implementation
[0018] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following description, it should be understood that the terms "upper," "inner," "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing the technical solution and do not indicate that the device or element referred to must have a specific orientation; therefore, they should not be construed as limitations on the present invention.
[0019] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. The terms "first," "second," "third," etc., are only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.
[0020] Figure 1 and Figure 2 This invention illustrates a radiation monitoring system for industrial steam supplied to a nuclear power plant, according to one embodiment of the present invention. This system can be used to monitor radiation leaks in internal pipelines of the nuclear power plant. It includes: a reactor 100; a steam generator 110 connected to the reactor 100 via pipelines; the steam generator 110 has a main steam pipeline 111 and a drain pipeline 131; a steam reheater 120 is connected to the steam generator 110 via the main steam pipeline 111; the steam reheater 120 has an external industrial steam pipeline 121 for external steam supply; the main steam pipeline 111 has a first sensor group 200 for detecting the gamma radioactivity of the steam; the drain pipeline 131 has a second sensor group 210 for detecting the gamma radioactivity of the steam in the external industrial steam pipeline 121; and the external industrial steam pipeline 121 has a third sensor group 220 for detecting the gamma radioactivity of the steam.
[0021] Several steam radioactivity detection sensors are installed on the main steam pipe 111, sewage pipe 131 and external industrial steam pipe 121 on the steam generator 110 to detect leaks in the main steam pipe 111, sewage pipe 131 and external industrial steam pipe 121. This enables comprehensive leak monitoring of the pipes in the secondary and tertiary heat exchange loops of the nuclear power plant, effectively preventing radioactive nuclides from leaving the plant through the external steam pipes.
[0022] In one specific embodiment, the first sensor group 200, the second sensor group 310 210, and the third sensor group 320 220 are sodium iodide sensors, and the sodium iodide sensors are wrapped with a lead protective layer to reduce external influences.
[0023] Figure 1 and Figure 2 The first shielding unit, in one embodiment, may include a first sensor group 200, a second sensor group 310 210, and a third sensor group 320 220, which are several steam radioactivity detection sensors. The four steam radioactivity detection sensors are evenly distributed around the pipe, with four in a circle forming a set and two sets forming a sensor group. Since the direction of the gamma rays produced by the decay of radioactive nuclides is isotropic, based on a comprehensive consideration of high detection efficiency and low cost, each radiation monitoring instrument is equipped with four sodium iodide detectors, arranged at 90° around the pipe.
[0024] Figure 1 and Figure 2 The first shielding unit, in one embodiment, may include a first switching valve 300 on the main steam pipe 111, a second switching valve on the drain pipe 131, and a third switching valve on the external industrial steam supply pipe 121. The first switching valve 300 can control the flow of fluid in the main steam pipe 111, the second switching valve can control the flow of fluid in the drain pipe 131, and the third switching valve can control the flow of fluid in the external industrial steam supply pipe 121.
[0025] Figures 1 to 4 This invention illustrates a radiation monitoring method for industrial steam supplied by a nuclear power plant, according to one embodiment of the present invention. This method can be used to monitor radiation leaks in pipelines within a nuclear power plant and may include the following steps: Step S1: Collect historical leakage records and leakage severity of the main steam pipe 111, the drain pipe 131 of the steam generator 110, and the external industrial steam supply pipe 121 of the steam generator 110. Step S2: Based on historical leakage records and leakage severity, select corresponding monitoring points on the main steam pipeline 111 of the steam generator 110, the drain pipeline 131 of the steam reheater 120, and the external industrial steam supply pipeline 121 of the steam reheater 120. Step S3: Place several sets of steam radioactivity detection sensors on the main steam pipe 111 of the steam generator 110, the sewage pipe 131 of the steam generator 110, and the monitoring point on the external industrial steam supply pipe 121. The first sensor group 200 and the second sensor group 210 are set on the main steam pipe 111, and the third sensor group 220 is set on the external industrial steam supply pipe 121. Step S4: When the first sensor group 200, the second sensor group 310 210 and the third sensor group 320 220 detect that the γ radioactivity activity is greater than the first safety value, a first alarm signal is issued. Step S5: When the manager receives the first alarm, he opens the pipeline to take liquid samples at the location where the first alarm signal was issued, and performs gamma radioactivity detection again. If the gamma radioactivity detection value is greater than the first safety value again, the leaking steam generator 110 is identified, the leak point is investigated, and the leak point is sealed. Step S6: When the first sensor group 200, the second sensor group 310 210 and the third sensor group 320 220 detect that the γ radioactivity activity is greater than the second safety value, a second alarm signal is issued. Step S7: Identify the pipe where the steam generator 110 is leaking, locate the leak point, shut off the steam supply pipe and the drain pipe 131 of the steam generator 110, and seal the leak point.
[0026] Several steam radioactivity detection sensors are installed on the main steam pipe 111, the sewage pipe 131, and the external industrial steam supply pipe 121 on the steam generator 110 to detect leaks in the main steam pipe 111, the sewage pipe 131, and the external industrial steam supply pipe 121. When the leakage exceeds the first safety value, personnel are arranged to conduct a re-inspection. If it is found that it still exceeds the first safety value, leakage investigation is carried out. When the leakage exceeds the second safety value, the main steam pipe 111 and the sewage pipe 131 of the steam generator 110 are shut off, and the leak point is immediately detected. This can timely, effectively, and reliably prevent radioactive nuclides leaking into the secondary coolant under abnormal operating conditions from leaving the factory through the external steam supply pipe.
[0027] Understandably, the shutdown operation of the steam supply pipe and the drain pipe 131 of the steam generator 110 in step s5 is not performed immediately. The shutdown of the steam supply pipe and the drain pipe 131 of the steam generator 110 is only performed after a period of time has passed since the leak was checked and no leak has been found.
[0028] In one specific embodiment, if no leak is found 24 hours after the leak point has been investigated, the steam supply pipe and the drain pipe 131 of the steam generator 110 are shut off.
[0029] In one specific embodiment, gamma radioactivity is detected again, and if the gamma radioactivity level is lower than the first safety value, the frequency of manual checks is increased.
[0030] Figure 3 and Figure 4 The first shielding unit, as shown in one embodiment, may include a first sensor group 200 with a first safety value of 4 × 10⁻⁶. 4 Bq / m 3 The first safety value for the second sensor group 210 is 9×10 5 Bq / m 3 The first safety value for the third sensor group 220 is 3×10 3Bq / m 3 When the value detected by any of the sensors in the first sensor group 200, the second sensor group 210, and the third sensor group 220 exceeds the first safety value, a first alarm signal is issued.
[0031] Understandably, the first safety value is different because the first sensor group, the second sensor group, and the third sensor are located in different pipe positions, and each pipe itself contains different levels of radiation activity.
[0032] Figure 3 and Figure 4 The first shielding unit, in one embodiment, may include a second safety value of 4 × 10⁻⁶ for a first sensor group 200. 6 Bq / m 3 The second safety value of the second sensor group 210 is 9×10 7 Bq / m 3 The second safety value for the third sensor group 220 is 3 × 10⁻⁶. 4 Bq / m 3 When the value detected by any of the first sensor group 200, the second sensor group 210, and the third sensor group 220 exceeds the second safety value, a second alarm signal will be issued.
[0033] Understandably, the second safety value differs because the first, second, and third sensor groups are located in different pipe positions, and each pipe itself contains different levels of radiation activity.
[0034] Figure 3 and Figure 4 In one embodiment, the first shielding unit may include, in steps S2 and S4, the first sensor group 200 detecting the vapor leakage rate, which is calculated based on the gamma radioactivity and the following formula: ; In the formula, q is the steam leakage rate, with units of kg·s. -1 n is 16 The gamma radioactivity of N, measured in s. -1 Q v Steam flow rate, unit: kg·s -1 ;ρ P Main loop water density, kg·m -3 Q P Main loop water flow rate, kg·s -1 Q P Branch loop water flow rate, kg·s -1 λ is the decay constant, s -1T represents the main loop water circulation cycle in seconds (s); L1 represents the length of the pipe from the reactor active zone outlet to the hot end of the steam generator in meters (m); S1 represents the main loop pipe area in square meters (m²); m represents the number of heat transfer tubes in the steam generator; L2 represents the pipe length from the hot end of the steam generator to the point of damage to the heat transfer tube in meters (m); S2 represents the cross-sectional area of the heat transfer tube in square meters (m²). 2 L3 is the pipe length from the steam outlet of the steam generator to the detector, in meters (m); S3 is the cross-sectional area of the steam pipe, in square meters (m²). 2 ;ρ v This refers to the density of steam, expressed in kg·m³. -3 Q v Steam flow rate, unit: kg·s -1 t1 is the time it takes for the main loop water to pass through the reactor active zone, in seconds; t2 is... 16 N is the diffusion time from the point of failure in the self-heating pipe to the steam outlet of the steam generator, measured in seconds; k is the diffusion time of the detector in the main steam pipe. 16 The detection efficiency of N, where N is the nuclear density of the water in the main loop of the reactor core, in kg. -1 σ(E) is the reaction cross-sectional area at neutron energy E, in m². 2 φn(E)dE represents the neutron flux rate in the reactor active region, from energy E to E+d, in m³ / s. -2 ·s -1 Eth neutron threshold energy, in MeV.
[0035] Understandably, the parameters in the formula are obtained based on reactor design parameters and various actual test parameters.
[0036] Figure 3 and Figure 4 In one embodiment, the first shielding unit may include, in steps S2 and S4, issuing a first alarm signal when the first safe value of the first steam leakage rate of the first sensor group 200 is greater than 4 L / h, and issuing a second alarm signal when the first safe value of the first steam leakage rate detected by the first sensor is greater than 70 L / h. The safe value of the leakage rate is calculated based on the radiation activity of the first sensor group 200, and is not the actual detected value.
[0037] Figure 3 and Figure 4 In one embodiment, the first shielding unit may include step S5, in which, when the manager receives the second alarm signal from the first sensor group 200 and the second sensor group 210, if the leak point cannot be detected after 24 hours of investigation, the unit needs to be withdrawn to the hot shutdown condition. The withdrawal of the unit to the hot shutdown condition is the operation process of the nuclear power unit transitioning from normal operation to short-term shutdown.
[0038] Figure 3and Figure 4 In one embodiment, the first shielding unit may include step S3, in which, upon receiving a first alarm signal, the wastewater from the drain pipe 131 of the steam generator 110 is switched to the nuclear island waste liquid treatment channel.
[0039] Figure 3 and Figure 4 As shown in step S2, if there is no record of leakage in the past, a monitoring point is set within 2-4 meters of the main steam pipeline 111 near the steam generator 110, a monitoring point is set within 2-4 meters of the drain pipeline 131 near the steam reheater 120, and a monitoring point is set within 2-4 meters of the external industrial steam pipeline 121 near the steam reheater 120.
[0040] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.
Claims
1. A radiation monitoring system for industrial steam supplied by a nuclear power plant, characterized in that, include: A steam generator (110) is connected to the reactor (100) via piping. The steam generator (110) is provided with a main steam pipe (111) and a drain pipe (131). A steam reheater (120) is connected to the steam generator (110) via the main steam pipe (111). The steam reheater (120) is provided with an external industrial steam pipe (121) for external steam supply. The main steam pipe (111) is provided with a first sensor group (200) for detecting the gamma radioactivity activity of the steam. The sewage pipe (131) is equipped with a second sensor (310) group (210) for detecting the gamma radioactivity of the steam in the external industrial steam pipe (121), the external industrial steam pipe (121) is equipped with a third sensor (320) group (220) for detecting the gamma radioactivity of the steam, the main steam pipe (111) is equipped with a first switch valve (300), the sewage pipe (131) is equipped with a second switch valve, and the external industrial steam pipe (121) is equipped with a third switch valve.
2. The radiation monitoring system for industrial steam supplied by a nuclear power plant according to claim 1, characterized in that, The first sensor group (200), the second sensor group (310) (210) and the third sensor group (320) (220) are a number of steam radioactivity detection sensors. The four steam radioactivity detection sensors are evenly distributed around the pipe, with four in a circle forming a set and two sets forming a sensor group.
3. A method for monitoring radiation from industrial steam supplied by a nuclear power plant, characterized in that, Includes the following steps: Step S1: Collect historical leakage records and leakage severity of the main steam pipe (111) of the steam generator (110), the drain pipe (131) of the steam generator (110) and the external industrial steam supply pipe (121); Step S2: Based on historical leakage records and leakage severity, select corresponding monitoring points on the main steam pipeline (111) of the steam generator (110), the drain pipeline (131) of the steam reheater (120), and the external industrial steam pipeline (121) of the steam reheater (120). Step S3: Place several sets of steam radioactivity detection sensors on the main steam pipe (111) of the steam generator (110), the sewage pipe (131) of the steam generator (110), and the monitoring point on the external industrial steam pipe (121). The sensors set on the main steam pipe (111) are the first sensor group (200) and the second sensor group (310) (210), and the sensors set on the external industrial steam pipe (121) are the third sensor group (320) (220). Step S4: When the first sensor group (200), the second sensor group (310) (210) and the third sensor group (320) (220) detect that the γ radioactivity activity is greater than the first safety value, a first alarm signal is issued. Step S5: When the manager receives the first alarm, he opens the pipeline to take liquid samples at the location where the first alarm signal was issued, and performs gamma radioactivity detection again. When the gamma radioactivity detection is greater than the first safety value again, he identifies the steam generator (110) that is leaking, investigates the leak point, and seals the leak point. Step S6: When the first sensor group (200), the second sensor group (310) (210), and the third sensor group (320) (220) detect that the γ radioactivity activity is greater than the second safety value, a second alarm signal is issued. Step S7: Identify the pipe where the steam generator (110) is leaking, investigate the leak point, shut off the steam supply pipe and the drain pipe (131) of the steam generator (110), and seal the leak point.
4. A radiation monitoring method for industrial steam supplied by a nuclear power plant according to claim 3, characterized in that, The first safety value of the first sensor group (200) is 4×10 4 Bq / m 3 The first safety value of the second sensor group (210) is 9×10 5 Bq / m 3 The first safety value of the third sensor group (220) is 3 × 10⁻⁶. 3 Bq / m 3 .
5. A radiation monitoring method for industrial steam supplied by a nuclear power plant according to claim 3, characterized in that, The second safety value of the first sensor group (200) is 4 × 10 6 Bq / m 3 The second safety value of the second sensor group (210) is 9×10 7 Bq / m 3 The second safety value of the third sensor group (220) is 3 × 10⁻⁶. 4 Bq / m 3 .
6. A radiation monitoring method for industrial steam supplied by a nuclear power plant according to claim 3, characterized in that, In steps S2 and S4, the first sensor group (200) needs to detect the steam leakage rate. The steam leakage rate is calculated based on the gamma radioactivity and the following formula: ; In the formula, q is the steam leakage rate, with units of kg·s. -1 n is 16 The gamma radioactivity of N, measured in s. -1 Q v Steam flow rate, unit: kg·s -1 ; ρ P Main loop water density, kg·m -3 Q P Main loop water flow rate, kg·s -1 Q P Branch loop water flow rate, kg·s -1 λ is the decay constant, s -1 T represents the main loop water circulation cycle in seconds (s); L1 represents the length of the pipe from the reactor active zone outlet to the hot end of the steam generator in meters (m); S1 represents the main loop pipe area in square meters (m²); m represents the number of heat transfer tubes in the steam generator; L2 represents the pipe length from the hot end of the steam generator to the point of damage to the heat transfer tube in meters (m); S2 represents the cross-sectional area of the heat transfer tube in square meters (m²). 2 L3 is the pipe length from the steam outlet of the steam generator to the detector, in meters (m); S3 is the cross-sectional area of the steam pipe, in square meters (m²). 2 ;ρ v This refers to the density of steam, expressed in kg·m³. -3 Q v Steam flow rate, unit: kg·s -1 t1 is the time it takes for the main loop water to pass through the reactor active zone, in seconds; t2 is... 16 N is the diffusion time from the point of failure in the self-heating pipe to the steam outlet of the steam generator, measured in seconds; k is the diffusion time of the detector in the main steam pipe. 16 The detection efficiency of N, where N is the nuclear density of the water in the main loop of the reactor core, in kg. -1 σ(E) is the reaction cross-sectional area at neutron energy E, in m². 2 φn(E)dE represents the neutron flux rate in the reactor active region, from energy E to E+d, in m³ / s. -2 ·s -1 Eth neutron threshold energy, in MeV.
7. A radiation monitoring method for industrial steam supplied by a nuclear power plant according to claim 6, characterized in that, In steps S2 and S4, when the first safe value of the first steam leakage rate of the first sensor group (200) is greater than 4 L / h, a first alarm signal is issued; when the first safe value of the first steam leakage rate detected by the first sensor group (200) is greater than 70 L / h, a second alarm signal is issued.
8. A radiation monitoring method for industrial steam supplied by a nuclear power plant according to claim 3, characterized in that, In step S5, when the manager receives the second alarm signal from the first sensor group and the second sensor group, if the leak point cannot be detected after 24 hours of investigation, the unit needs to be withdrawn to the hot shutdown condition. The withdrawal of the unit to the hot shutdown condition is the operation process of the nuclear power unit transitioning from normal operation to short-term shutdown.
9. A radiation monitoring method for industrial steam supplied by a nuclear power plant according to claim 3, characterized in that, In step S3, when the first alarm signal is received, the wastewater from the steam generator's drain pipe is switched to the nuclear island waste liquid treatment channel.
10. A radiation monitoring method for industrial steam supplied by a nuclear power plant according to claim 3, characterized in that, In step S2, if there is no record of leakage in the past, a monitoring point is set within 2-4 meters of the main steam pipeline (111) near the steam generator (110), a monitoring point is set within 2-4 meters of the sewage pipeline (131) near the steam reheater (120), and a monitoring point is set within 2-4 meters of the external industrial steam pipeline (121) near the steam reheater (120).