A method and control system for handling SGTR accidents in pressurized water reactor nuclear power plants

Abstract

The invention discloses a method and control system for handling SGTR accidents in a pressurized water reactor nuclear power plant. Firstly, an automatic SGTR accident identification signal is set to isolate a damaged SG loop PRS, thereby controlling the radioactive release on the secondary side of the damaged SG; then, the primary loop is continuously cooled and depressurized to ensure that the primary loop can reach sufficient supercooling and water loading; then, the water injection flow rate of the HPMT is controlled to achieve a preliminary balance between the pressures on the primary and secondary sides of the damaged SG, thereby stabilizing the state of the nuclear power plant and stopping the leakage of the radioactive cooler on the primary side of the damaged SG to the secondary side; finally, the primary loop is cooled to a cold shutdown state, thereby forming a set of scientific and reasonable methods for handling SGTR accidents, which can effectively handle SGTR accidents in pressurized water reactor nuclear power plants based on a passive emergency core cooling system and a secondary side passive residual heat removal system, and expand the scope of handling SGTR accidents in nuclear power plants.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power plant accident processing, and in particular to a pressurized water reactor nuclear power plant SGTR accident processing method and control system. Background Art

[0002] After a steam generator heat transfer tube rupture accident (SGTR) occurs in a pressurized water reactor nuclear power plant, the radioactive coolant in the primary circuit flows into the secondary side of the damaged steam generator (damaged SG) through the rupture of the heat transfer tube, resulting in an increase in the radioactivity of the secondary circuit system. If the off-site power supply is lost or the bypass fails during the accident, the radioactive coolant will be discharged into the atmosphere through the damaged SG atmospheric release valve or safety valve. Therefore, the operator needs to take corresponding recovery measures to reduce the radioactive release of the damaged SG. The existing SGTR response strategies in China are mainly used to respond to SGTR accidents in active nuclear power plants or SGTR accidents in primary-side passive nuclear power plants, and cannot effectively respond to SGTR accidents in pressurized water reactor nuclear power plants designed with passive emergency core cooling systems and secondary-side passive residual heat removal systems.

[0003] In view of this, this application is hereby filed. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the existing SGTR coping method is not suitable for SGTR accidents in pressurized water reactor nuclear power plants. The purpose is to provide a method and control for handling SGTR accidents in pressurized water reactor nuclear power plants, which can stabilize the state of the nuclear power plant, stop the leakage from the primary side to the secondary side of the damaged steam generator, and cool down and depressurize the nuclear power plant to a cold shutdown state after the leakage stops.

[0005] The present invention is achieved through the following technical solutions:

[0006] on the one hand,

[0007] The present invention provides a method for handling SGTR accidents in a pressurized water reactor nuclear power plant, comprising the following steps:

[0008] Setting an SGTR accident automatic identification signal, isolating a damaged SG loop PRS according to the SGTR accident automatic identification signal;

[0009] Identify the SGTR accident characteristics and perform the following steps based on the SGTR accident characteristics:

[0010] Continuously cool down the primary circuit until the subcooling degree of the primary circuit meets the requirements;

[0011] During the cooling process, the pressure of the primary circuit is continuously reduced until the water loading of the pressurizer of the primary circuit is restored;

[0012] After the temperature and pressure reduction are completed, stop the HPMT from injecting water into the primary circuit;

[0013] The intact SG loop PRS is used to perform secondary cooling of the primary circuit until the PWR nuclear power plant is in a cold shutdown state.

[0014] Further,

[0015] The SGTR accident automatic identification signals include: steam generator N16 monitoring abnormal signal, steam total γ activity abnormal signal, condenser extraction γ activity abnormal signal, steam generator sewage γ activity abnormal signal and steam generator narrow range water level uncontrolled rise signal.

[0016] Furthermore,

[0017] Before cooling down a circuit, the following steps are included: Confirm that the water supply side and steam side of the damaged SG have been automatically isolated.

[0018] Furthermore,

[0019] Confirming that the water and steam sides of the damaged SG have been automatically isolated includes the following steps:

[0020] Confirm that the main water supply isolation valve and auxiliary water supply isolation valve of the damaged SG have been automatically isolated;

[0021] Confirm that the damaged SG loop PRS has been automatically isolated;

[0022] Confirm that the main steam isolation valve and bypass isolation valve are closed;

[0023] Increase the atmospheric relief valve setting value of the damaged SG;

[0024] Close the sewage pipeline, steam traps and air supply valve of the damaged SG.

[0025] Furthermore,

[0026] Continuous cooling of a circuit includes the following steps:

[0027] Use intact SG to continuously cool down the primary circuit;

[0028] If the intact SG is not available, the intact SG loop PRS is used to continuously cool the primary circuit system;

[0029] If the intact SG and the intact SG loop PRS are both unavailable, the RPPS system and the passive emergency cooling system are used to continuously cool the primary circuit system.

[0030] Furthermore,

[0031] The continuous cooling of a circuit using a good SG includes the following steps:

[0032] If only an SGTR accident occurs, the intact SG is controlled to continuously cool down the primary circuit at a normal cooling rate;

[0033] If the SGTR accident occurs simultaneously with other accidents, the intact SG is controlled to continuously cool down the primary circuit at the highest cooling rate.

[0034] Furthermore,

[0035] Continuously reducing the pressure of a circuit includes the following steps: Continuously reducing the pressure of a circuit by using a stabilizer-assisted spray or RPPS.

[0036] Furthermore,

[0037] After stopping the HPMT from injecting water into the primary circuit, the following steps are included: removing the core decay heat.

[0038] Furthermore,

[0039] Removing core decay heat includes the following steps:

[0040] Control the water volume of the primary circuit by controlling the flow of the primary circuit water supply system;

[0041] The pressure of one circuit is controlled by means of normal spray of the pressurizer and the electric heater of the pressurizer.

[0042] on the other hand,

[0043] The present invention provides a SGTR accident processing control system for a pressurized water reactor nuclear power plant, comprising:

[0044] The monitoring module is used to monitor the water level of the SG and the radioactivity of the secondary side of the SG. When the water level of the SG rises uncontrollably or the radioactivity of the secondary side of the SG is abnormal, the corresponding monitoring abnormal data is generated;

[0045] A signal generation module is used to generate an SGTR accident automatic identification signal based on monitoring abnormal data;

[0046] A PRS isolation control module is used to isolate the damaged SG loop PRS according to the SGTR accident automatic identification signal;

[0047] An SGTR accident identification module is used to identify the type of the SGTR accident automatic identification signal to obtain SGTR accident characteristics;

[0048] A cooling system control module, used to control the cooling system to continuously cool down the primary circuit according to the SGTR accident characteristics until the supercooling degree of the primary circuit meets the requirements;

[0049] The pressure reduction system control module is used to control the pressure reduction system to continuously reduce the pressure of the primary circuit during the cooling process until the water loading of the regulator of the primary circuit is restored;

[0050] The HPMT control module is used to control the HPMT to stop injecting water into the primary circuit after the temperature and pressure reduction are completed;

[0051] The PRS control module is used to control the intact SG loop PRS to perform secondary cooling on the primary loop until the pressurized water is in a cold shutdown state for the nuclear power plant.

[0052] Compared with the prior art, the present invention has the following advantages and beneficial effects: firstly, by setting the SGTR accident automatic identification signal to isolate the damaged SG loop PRS, the radioactive release on the secondary side of the damaged SG is controlled; then, by continuously reducing the temperature and pressure of the primary loop, it is ensured that the primary loop can reach sufficient supercooling and water loading; then, by controlling the water injection flow of the HPMT, the pressure on the primary and secondary sides of the damaged SG is initially balanced, thereby stabilizing the state of the nuclear power plant and stopping the leakage of the radioactive cooler on the primary side of the damaged SG to the secondary side; finally, the primary loop is cooled to a cold shutdown state, thereby forming a set of scientific and reasonable SGTR accident response methods, which can effectively respond to SGTR accidents of pressurized water reactor nuclear power plants based on a passive emergency core cooling system and a secondary side passive residual heat removal system, and expand the response scope of SGTR accident handling in nuclear power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0054] Figure 1 A schematic diagram of the structure of a primary circuit of a pressurized water reactor provided in Example 1 of the present invention;

[0055] Figure 2 A schematic flow chart of a method for handling an SGTR accident in a pressurized water reactor nuclear power plant provided in Example 1 of the present invention;

[0056] Figure 3 This is a schematic diagram of the structure of the SGTR accident handling control system for a pressurized water reactor nuclear power plant provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0057] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0058] Example 1

[0059] The existing SGTR response strategies in China are mainly used to respond to SGTR accidents in active nuclear power plants or SGTR accidents in primary-side passive nuclear power plants. They cannot effectively respond to SGTR accidents in pressurized water reactor nuclear power plants (stations) that are designed with passive emergency core cooling systems and secondary-side passive residual heat removal systems.

[0060] The passive emergency cooling system is equipped with a full pressure make-up water tank (HPMT), an injection tank, a external pressure water tank (RWST) and a pressure relief protection system (RPPS). Its safety function is to provide sufficient make-up water to the reactor coolant system after an accident. The safety function of the secondary side passive residual heat removal system (PRS) is to automatically start operation after an accident to remove the residual heat from the core.

[0061] Figure 1 The structure of the primary circuit of a pressurized water reactor is shown. An SGTR accident will cause a reduction in the amount of water in the reactor coolant system, but will not cause serious core damage. It will only cause the radioactive coolant in the primary circuit to leak into the secondary circuit system through the rupture of the heat transfer tube. An SGTR accident will cause the amount of water in the reactor coolant system to continue to decrease, triggering an emergency shutdown of the reactor and the automatic commissioning of the full pressure replenishment tank (HPMT) and the secondary passive residual heat removal system of the passive emergency cooling system. Among them, the HPMT injects boron-containing water into the reactor coolant system in a water recycling mode to maintain the water volume of the reactor system; the secondary passive residual heat removal system (PRS) is automatically commissioned to remove the residual heat of the core and automatically isolate the related valves of the secondary circuit of the damaged SG loop. Since the PRS system is located on the secondary side, the continuous operation of the damaged SG loop PRS will reduce the pressure of the damaged SG, making it difficult to balance the primary and secondary sides of the damaged SG.

[0062] Therefore, the present embodiment provides a method for handling SGTR accidents in pressurized water reactor nuclear power plants. First, an SGTR accident automatic identification signal is set (the PRS system is started in accordance with the SGTR accident automatic identification signal). According to the SGTR accident automatic identification signal, the damaged loop PRS system automatically isolates the related valves of the damaged SG loop secondary loop, so that the pressure of the damaged SG gradually increases; then the intact loop PRS system is used to cool the primary loop. As the primary loop system cools down and the water loading volume decreases, the pressurizer water level and pressure decrease, the HPMT injection flow will be balanced with the breach flow and the contraction of the primary loop coolant, and the primary loop pressure will approach an equilibrium value. Of course, the pressurizer spray or pressure relief protection system (RPPS) can also be used to manually reduce the reactor coolant system pressure until the pressures on the primary and secondary sides of the damaged SG are balanced and the SGTR breach flow stops. The water volume in the full pressure makeup tank (HPMT) is sufficient to ensure the safety of the reactor. During the accident, the pressure relief protection system (RPPS) will not be automatically activated, the core will not be exposed, and the injection tank does not need to be put into operation. Only the passive emergency cooling system and the secondary passive residual heat removal system (PRS) can be automatically put into operation to ensure the pressure balance of the primary and secondary sides of the damaged SG. After the status of the nuclear power plant (station) stabilizes, when the HPMT isolation conditions are reached, the HPMT needs to be manually isolated, and the primary water makeup system is used to maintain the pressurizer liquid level; the PRS system or the intact steam generator (or normal residual heat removal system) is used to cool the primary system; the normal spray of the pressurizer or the RPPS valve can also be used to reduce the primary pressure until the cold shutdown state is reached.

[0063] According to the above technical concept, the present embodiment provides a method for handling SGTR accidents in pressurized water reactor nuclear power plants, including setting SGTR accident automatic protection signals and formulating SGTR accident mitigation measures. The implementation process is as follows: Figure 1 As shown. Specifically including the following steps:

[0064] Step 1: Set an SGTR accident automatic identification signal, and isolate the damaged SG loop PRS according to the SGTR accident automatic identification signal.

[0065] After the steam generator heat transfer tube rupture accident, the radioactive coolant on the primary side leaked into the secondary circuit system through the rupture, the water level of the pressurizer continued to drop, the radioactivity on the secondary side of the steam generator was abnormal, and the main feed water control system of the steam generator automatically adjusted the main feed water flow. When the main feed water control system was unavailable, the water level of the damaged SG would rise uncontrollably. In addition, the operation of the secondary side passive residual heat removal system (PRS) would also cause the secondary side pressure of the damaged SG to continue to drop, and the primary and secondary side pressures of the damaged SG were difficult to balance, which was extremely unfavorable to preventing the damaged SG from overflowing.

[0066] Therefore, an SGTR accident automatic identification signal is set. After the PRS is automatically triggered, the SGTR accident automatic identification signal is used, such as: steam generator N16 monitoring abnormal signal, steam total γ activity abnormal signal, condenser extraction γ activity abnormal signal, steam generator sewage γ activity abnormal signal and steam generator narrow range water level uncontrolled rising signal, to isolate the damaged SG loop PRS and prevent the pressure of the damaged SG from continuing to drop.

[0067] Step 2: Identify the SGTR accident characteristics and execute steps 3 to 6 according to the SGTR accident characteristics.

[0068] After an SGTR accident occurs in a pressurized water reactor nuclear power plant (station) designed based on a passive emergency cooling system and a secondary side passive residual heat removal system (PRS), the damaged SG will show typical accident characteristics, such as uncontrolled rise of the steam generator water level in a narrow range, abnormal monitoring of the steam generator N16, abnormal total steam γ activity, and abnormal γ activity of the steam generator wastewater.

[0069] Therefore, the operator needs to quickly diagnose the SGTR accident according to the characteristics of the steam generator heat transfer tube rupture accident, and perform recovery operations to stabilize the nuclear power plant (station) state and stop the leakage from the primary side to the secondary side; when the water level of the damaged SG is restored, stop the water supply of the damaged SG. The operator can also verify the sequence and status of the automatically put-into non-safety-level systems to provide in-depth defense. Finally, by cooling the primary circuit, the nuclear power plant (station) is retreated to the cold shutdown state.

[0070] It should be noted that once a damaged SG is identified, the secondary side passive residual heat removal system (PRS) will automatically start and automatically isolate the damaged SG main feedwater isolation valve and the damaged SG steam side valve. Therefore, as a necessary step to stop the leakage from the primary circuit to the secondary circuit, the operator needs to confirm that the feedwater side and steam side of the damaged SG have been automatically isolated to limit the release of radioactivity. Confirming whether the feedwater side and steam side of the damaged SG have been automatically isolated includes the following steps:

[0071] Step 2.1: Confirm that the main water supply isolation valve and auxiliary water supply isolation valve of the damaged SG have been automatically isolated;

[0072] Step 2.2: Confirm that the damaged SG loop PRS has been automatically isolated;

[0073] Step 2.3: Confirm that the main steam isolation valve and bypass isolation valve are closed;

[0074] Step 2.4: Increase the atmospheric relief valve setting value of the damaged SG;

[0075] Step 2.5: Close the drain line, steam traps and air supply valve of the damaged SG.

[0076] If the water supply side and steam side of the damaged SG have been automatically isolated, the damaged SG loop PRS system will isolate the PRS system according to the automatic isolation signal (PRS system startup meets the SGTR accident automatic identification signal) to prevent the damaged SG pressure from continuing to drop. After the damaged SG secondary side is isolated, the damaged SG pressure will slowly rise.

[0077] Step 3: Continue to cool down the primary circuit until the subcooling degree of the primary circuit meets the requirements. Including:

[0078] Step 3.1: Use intact SG to continuously cool down the primary circuit;

[0079] Step 3.2: If the intact SG is not available, the intact SG loop PRS is used to continuously cool down the primary circuit system;

[0080] Step 3.3: If the intact SG and the intact SG loop PRS are both unavailable, the RPPS system and the passive emergency cooling system are used to continuously cool down the primary circuit system.

[0081] After an SGTR accident, the intact loop PRS is automatically started to cool the primary loop system (the damaged loop PRS has been automatically isolated). If only an SGTR accident occurs, the normal cooling rate can be used; if a superimposed accident occurs at the same time, the maximum cooling rate limited by the technical specification is required to maintain the primary loop water capacity, and there is no need to trigger the pressure relief protection system (RPPS). The operator can also use the intact steam generator to reduce the primary loop temperature to provide sufficient primary loop subcooling for the next step of reducing the pressure of the primary loop system to the damaged SG pressure, including the following two situations and response methods: (1) If the intact SG is not available, the secondary side passive residual heat removal system (PRS) is used for cooling; in the extremely unlikely operating condition, both the intact SG and the secondary side passive residual heat removal system are unavailable, and the RPPS system and the passive emergency cooling system can be used for cooling.

[0082] Step 4: During the cooling process, the pressure of the primary circuit is continuously reduced until the water capacity of the pressurizer of the primary circuit is restored. Since the injection signal of the full pressure replenishment tank (HPMT) stops the main pump, the pressurizer auxiliary spray or RPPS can be used to continuously reduce the pressure of the primary circuit.

[0083] During the cooling process of the primary circuit, the injection flow of the full pressure makeup tank (HPMT) and the primary circuit makeup system will gradually increase the primary circuit pressure until the breach flow is balanced with the total injection flow. Therefore, these injection flows must be terminated or controlled to terminate the leakage from the primary side to the secondary side. It should be noted that before terminating the leakage from the primary side to the secondary side, sufficient reactor coolant charge must be maintained, including sufficient primary circuit subcooling and pressurizer water charge, to terminate HPMT injection. The operator can use the normal spray of the pressurizer or the pressure relief protection system (RPPS) to reduce the primary circuit pressure; even if the operator does not take action, the reactor coolant system pressure can be effectively reduced by relying solely on the secondary side passive residual heat removal system (PRS). The leakage from the primary side to the secondary circuit will only stop after the primary circuit pressure and the pressure of the damaged SG are balanced.

[0084] It should be noted that the pressure of the primary circuit will continue to decrease until the water level of the pressurizer is restored. Under natural circulation conditions, a steam cavity may be generated on the upper part of the damaged SG. Since this phenomenon may cause the water level of the pressurizer to rise rapidly, the primary circuit pressure reduction operation should be terminated when the water level of the pressurizer is high to prevent water tightness.

[0085] Step 5: After the temperature and pressure are reduced, stop the HPMT from injecting water into the primary circuit to stop the leakage from the primary side to the secondary side of the damaged SG.

[0086] After steps 3 and 4, sufficient primary circuit subcooling, secondary side heat sink (secondary circuit passive residual heat removal system (PRS) or intact steam generator) and sufficient primary circuit coolant water volume have been established, so HPMT injection flow is no longer needed. The operator needs to terminate HPMT to stop the leakage from the primary side to the secondary side. After the HPMT injection flow is terminated, the primary side of the damaged SG will leak to the secondary side until the primary circuit pressure and the damaged SG pressure are balanced.

[0087] To prevent the damaged SG from leaking again, the operator can remove the core decay heat by controlling the flow of the primary water supply system, the pressurizer electric heater, and using the PRS or intact steam generator (normal residual heat removal system).

[0088] Step 6: Use the intact SG loop PRS to perform secondary cooling on the primary loop until the PWR NPP is in a cold shutdown state.

[0089] If the primary circuit pressure and the secondary side pressure of the damaged SG are balanced, the leakage from the primary side to the secondary side stops, and the initial safety state is reached. At this time, the operator needs to take a series of operations to cool the reactor to the cold shutdown condition at a controllable cooling rate, including reducing the radioactive contamination of the secondary circuit and restarting the main pump to ensure uniform coolant temperature and boron concentration. At the same time, the operator should select the optimal SGTR post-accident cooling method (exhaust steam, blowdown and back injection while dissipating heat to the environment) according to the current power plant status.

[0090] In summary, the SGTR accident handling method for a pressurized water reactor nuclear power plant provided in this embodiment first isolates the damaged SG loop PRS by setting an SGTR accident automatic identification signal, thereby controlling the radioactive release on the secondary side of the damaged SG; then, by continuously cooling and depressurizing the primary loop, it is ensured that the primary loop can achieve sufficient subcooling and water loading; then, by controlling the water injection flow of the HPMT, the pressures on the primary and secondary sides of the damaged SG are initially balanced, thereby stabilizing the state of the nuclear power plant and stopping the leakage of the radioactive cooler on the primary side of the damaged SG to the secondary side; finally, the primary loop is cooled to a cold shutdown state, thereby forming a set of scientific and reasonable SGTR accident response methods, which can effectively respond to SGTR accidents in pressurized water reactor nuclear power plants based on a passive emergency core cooling system and a secondary side passive residual heat removal system, and expand the response scope of SGTR accident handling in nuclear power plants.

[0091] Example 2

[0092] This embodiment provides a control system corresponding to the SGTR accident handling method for a pressurized water reactor nuclear power plant described in Embodiment 1, which is used to realize digital control of SGTR accident handling for a pressurized water reactor nuclear power plant. The structure of the SGTR accident handling control system for a pressurized water reactor nuclear power plant is as follows: Figure 3 As shown, including:

[0093] The monitoring module is used to monitor the water level of the SG and the radioactivity of the secondary side of the SG. When the water level of the SG rises uncontrollably or the radioactivity of the secondary side of the SG is abnormal, the corresponding monitoring abnormal data is generated;

[0094] A signal generation module is used to generate an SGTR accident automatic identification signal based on monitoring abnormal data;

[0095] A PRS isolation control module is used to isolate the damaged SG loop PRS according to the SGTR accident automatic identification signal;

[0096] An SGTR accident identification module is used to identify the type of the SGTR accident automatic identification signal to obtain SGTR accident characteristics;

[0097] A cooling system control module, used to control the cooling system to continuously cool down the primary circuit according to the SGTR accident characteristics until the supercooling degree of the primary circuit meets the requirements;

[0098] The pressure reduction system control module is used to control the pressure reduction system to continuously reduce the pressure of the primary circuit during the cooling process until the water loading of the regulator of the primary circuit is restored;

[0099] The HPMT control module is used to control the HPMT to stop injecting water into the primary circuit after the temperature and pressure reduction are completed;

[0100] The PRS control module is used to control the intact SG loop PRS to perform secondary cooling on the primary loop until the pressurized water is in a cold shutdown state for the nuclear power plant.

[0101] It should be noted that the system provides corresponding control interfaces for operators to operate pressurized water on relevant equipment in nuclear power plants, including:

[0102] Signal indications of nuclear measurement system status, steam generator water level, steam generator pressure, pressurizer water level, pressurizer pressure, core outlet subcooling, containment pressure and radioactive dose rate, main pump operation status, steam generator secondary side radioactivity monitoring, main feed water flow, full pressure make-up water tank (HPMT) water level, secondary side passive residual heat removal system (PRS) status, primary water make-up system status and pressurizer safety valve and steam generator safety valve gauge atmospheric release valve status, pressure relief protection system (RPPS) valve status, pressurizer spray valve status, PRS isolation valve status, main steam isolation valve status, and control interfaces such as passive emergency cooling system, containment isolation system, containment spray system, primary water make-up system, steam generator isolation system, steam generator emergency feed water system, steam generator atmospheric discharge system, secondary side passive residual heat removal system, pressurizer pressure control system, and steam generator sewage system.

[0103] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for handling SGTR accidents in pressurized water reactor nuclear power plants, It is characterized in that The following steps are involved: An SGTR accident automatic identification signal is set, and the damaged SG loop PRS is isolated according to the SGTR accident automatic identification signal; wherein the SGTR accident automatic identification signal includes: steam generator N16 monitoring abnormal signal, steam total γ activity abnormal signal, condenser extraction γ activity abnormal signal, steam generator sewage γ activity abnormal signal and steam generator narrow range water level uncontrolled rising signal; Identify the SGTR accident characteristics and perform the following steps based on the SGTR accident characteristics: Confirm that the water supply side and steam side of the damaged SG have been automatically isolated; wherein the confirmation that the water supply side and steam side of the damaged SG have been automatically isolated includes the following steps: confirm that the main water supply isolation valve and the auxiliary water supply isolation valve of the damaged SG have been automatically isolated; confirm that the damaged SG loop PRS has been automatically isolated; confirm that the main steam isolation valve and the bypass isolation valve have been closed; increase the setting value of the atmospheric release valve of the damaged SG; close the sewage pipeline, each steam trap and air supply valve of the damaged SG; Continuously cool down the primary circuit until the supercooling degree of the primary circuit meets the requirement; wherein the continuously cooling down the primary circuit comprises the following steps: continuously cool down the primary circuit using an intact SG; if the intact SG is unavailable, continuously cool down the primary circuit system using an intact SG loop PRS; if both the intact SG and the intact SG loop PRS are unavailable, continuously cool down the primary circuit system using an RPPS system and a passive emergency cooling system; During the cooling process, the pressure of the primary circuit is continuously reduced until the water loading of the pressurizer of the primary circuit is restored; After the temperature and pressure reduction are completed, stop the HPMT from injecting water into the primary circuit; The intact SG loop PRS is used to perform secondary cooling of the primary circuit until the PWR nuclear power plant is in a cold shutdown state.

2. A method for handling SGTR accidents in a pressurized water reactor nuclear power plant according to claim 1, It is characterized in that The continuous cooling of a circuit using a good SG comprises the following steps: If only an SGTR accident occurs, the intact SG is controlled to continuously cool down the primary circuit at a normal cooling rate; If the SGTR accident occurs simultaneously with other accidents, the intact SG is controlled to continuously cool down the primary circuit at the highest cooling rate.

3. A method for handling SGTR accidents in a pressurized water reactor nuclear power plant according to claim 1, It is characterized in that The method of continuously reducing the pressure of a circuit comprises the following steps: continuously reducing the pressure of a circuit by using a pressure stabilizer-assisted spray or RPPS.

4. A method for handling SGTR accidents in a pressurized water reactor nuclear power plant according to claim 1, It is characterized in that After stopping the HPMT from injecting water into the primary circuit, the following steps are included: removing the core decay heat.

5. A method for handling SGTR accidents in a pressurized water reactor nuclear power plant according to claim 4, It is characterized in that The process of removing the core decay heat comprises the following steps: Control the water volume of the primary circuit by controlling the flow of the primary circuit water supply system; The pressure of one circuit is controlled by means of normal spray of the pressurizer and the electric heater of the pressurizer.

6. A SGTR accident handling control system for a pressurized water reactor nuclear power plant, It is characterized in that include: The monitoring module is used to monitor the water level of the SG and the radioactivity of the secondary side of the SG. When the water level of the SG rises uncontrollably or the radioactivity of the secondary side of the SG is abnormal, the corresponding monitoring abnormal data is generated; A signal generation module is used to generate an SGTR accident automatic identification signal according to the monitoring abnormal data; wherein the SGTR accident automatic identification signal includes: a steam generator N16 monitoring abnormal signal, a steam total γ activity abnormal signal, a condenser extraction γ activity abnormal signal, a steam generator sewage γ activity abnormal signal and a steam generator narrow range water level uncontrolled rising signal; A PRS isolation control module is used to isolate the damaged SG loop PRS according to the SGTR accident automatic identification signal; An SGTR accident identification module is used to identify the type of the SGTR accident automatic identification signal to obtain SGTR accident characteristics; Confirm that the water supply side and steam side of the damaged SG have been automatically isolated; the confirmation that the water supply side and steam side of the damaged SG have been automatically isolated includes the following steps: confirm that the main water supply isolation valve and auxiliary water supply isolation valve of the damaged SG have been automatically isolated; confirm that the damaged SG loop PRS has been automatically isolated; confirm that the main steam isolation valve and bypass isolation valve have been closed; increase the setting value of the atmospheric release valve of the damaged SG; close the sewage pipeline, each steam trap and air supply valve of the damaged SG; A cooling system control module is used to control the cooling system to continuously cool down the primary circuit according to the SGTR accident characteristics until the supercooling degree of the primary circuit meets the requirements; wherein the continuous cooling of the primary circuit comprises the following steps: using an intact SG to continuously cool down the primary circuit; if the intact SG is unavailable, using an intact SG loop PRS to continuously cool down the primary circuit system; if both the intact SG and the intact SG loop PRS are unavailable, using the RPPS system and the passive emergency cooling system to continuously cool down the primary circuit system; The pressure reduction system control module is used to control the pressure reduction system to continuously reduce the pressure of the primary circuit during the cooling process until the water loading of the regulator of the primary circuit is restored; The HPMT control module is used to control the HPMT to stop injecting water into the primary circuit after the temperature and pressure reduction are completed; The PRS control module is used to control the intact SG loop PRS to perform secondary cooling on the primary loop until the pressurized water is in a cold shutdown state for the nuclear power plant.

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