阅读说明：本技术 一种压水堆核电厂安注箱自动隔离系统以及方法 (Automatic isolation system and method for safety injection tank of pressurized water reactor nuclear power plant ) 是由 王振营 黄宇 焦振营 于枫婉 龚铭游 于 2019-09-17 设计创作，主要内容包括：本发明提供了一种压水堆核电厂安注箱自动隔离系统以及方法,该自动隔离系统包括温度压力测量模块和控制模块,温度压力测量模块安装在安注箱内,用于实时采集安注箱内气空间的温度和压力,并输出有效的温度和压力测量信号；控制模块连接温度压力测量模块和安注箱隔离阀,用于接收温度和压力测量信号,并依据温度和压力测量信号判断安注箱是否已经排空；若是,则输出自动隔离信号控制安注箱隔离阀自动关闭。本发明提供的核电厂安注箱自动隔离系统以及方法,可以实现任何事故工况下,安注箱排空时自动地隔离安注箱,既保证安注箱内的含硼水全部注入一回路,又确保氮气不会注入一回路,从而保证堆芯安全,提升反应堆的安全水平。(The invention provides an automatic isolation system and method for a safety injection box of a pressurized water reactor nuclear power plant, wherein the automatic isolation system comprises a temperature and pressure measurement module and a control module, wherein the temperature and pressure measurement module is arranged in the safety injection box and is used for acquiring the temperature and the pressure of an air space in the safety injection box in real time and outputting effective temperature and pressure measurement signals; the control module is connected with the temperature and pressure measuring module and the safety injection tank isolating valve and used for receiving temperature and pressure measuring signals and judging whether the safety injection tank is emptied or not according to the temperature and pressure measuring signals; if yes, an automatic isolation signal is output to control the isolation valve of the safety injection tank to be automatically closed. The automatic isolation system and method for the safety injection tank of the nuclear power plant can automatically isolate the safety injection tank when the safety injection tank is emptied under any accident condition, so that the boron-containing water in the safety injection tank is ensured to be completely injected into a primary circuit, and nitrogen is ensured not to be injected into the primary circuit, thereby ensuring the safety of a reactor core and improving the safety level of a reactor.)

1. The utility model provides a PWR nuclear power plant safety injection case automatic isolation system which characterized in that includes:

the temperature and pressure measuring module is arranged in the safety injection box and is used for acquiring the temperature and the pressure of an air space in the safety injection box in real time and outputting effective temperature and pressure measuring signals;

the control module is connected with the temperature and pressure measuring module and the safety injection tank isolating valve and used for receiving the temperature and pressure measuring signals and judging whether the safety injection tank is emptied or not according to the temperature and pressure measuring signals; if yes, an automatic isolation signal is output to control the isolation valve of the safety injection box to be automatically closed.

2. The automatic isolation system of the safety injection tank of the pressurized water reactor nuclear power plant according to claim 1, wherein the control module is further configured to establish a safety injection tank emptying threshold curve, and the safety injection tank emptying threshold curve is a corresponding relation between pressure and temperature of the safety injection tank;

the control module is further used for judging that the safety injection box is emptied when the coordinate points corresponding to the temperature and pressure measurement signals are located in the area above the safety injection box emptying threshold curve.

3. The automatic isolation system of a safety tank of a pressurized water reactor nuclear power plant according to claim 1, wherein the temperature and pressure measurement module comprises:

the temperature and pressure monitoring instruments are arranged redundantly and are arranged in the safety injection box and are used for acquiring temperature and pressure of an air space in the safety injection box in real time to generate temperature and pressure measuring signals;

and the validity checking module is connected with the temperature and pressure monitoring instrument and used for checking the electrical validity of the temperature and pressure measuring signals according to a preset measuring range, marking the measuring signals positioned in the measuring range as valid, and marking the measuring signals beyond the measuring range as invalid.

4. The automatic isolation system of a safety tank of a pressurized water reactor nuclear power plant according to claim 3, further comprising: the isolation valve driving module is connected with the control module and the safety injection box isolation valve and is used for receiving and driving the safety injection box isolation valve to close according to the automatic isolation signal;

the isolation valve driving module is also connected with a manual control switch and used for receiving a manual control signal output by the manual control switch and driving the isolation valve of the safety injection box to be opened or closed according to the manual control signal; the manual control signal has a higher priority than the automatic isolation signal.

5. The automatic isolation system of a safety injection tank of a pressurized water reactor nuclear power plant according to claim 4, further comprising a mode selection module connected to the isolation valve driving module, wherein the mode selection module is further connected to a test and bypass switch for controlling the isolation valve driving module to isolate the automatic isolation signal according to an operation command output by the test and bypass switch.

6. The automatic isolation system of a safety injection tank of a pressurized water reactor nuclear power plant according to claim 3, wherein the control module is further configured to give an alarm indication when the automatic isolation signal is output;

and the control module is also used for not performing emptying judgment on the safety injection tank when each temperature measurement signal or each pressure measurement signal is identified to be invalid, and giving a system fault indication.

7. An automatic isolation method for a safety injection tank of a pressurized water reactor nuclear power plant is characterized by comprising the following steps:

collecting the temperature and pressure of the air space in the safety injection box in real time, and outputting effective temperature and pressure measurement signals;

receiving the temperature and pressure measurement signals, and judging whether the safety injection tank is emptied or not according to the temperature and pressure measurement signals; if yes, an automatic isolation signal is output to control the isolation valve of the safety injection box to be automatically closed.

8. The method of claim 7, further comprising:

establishing a safety injection box emptying threshold curve, wherein the safety injection box emptying threshold curve is a corresponding relation between the pressure and the temperature of a safety injection box;

and when the coordinate points corresponding to the temperature and pressure measurement signals are located in the area above the safety injection tank emptying threshold curve, judging that the safety injection tank is emptied.

9. The automatic isolation method of the safety injection tank of the pressurized water reactor nuclear power plant according to claim 7, wherein the step of collecting the temperature and the pressure of the gas space in the safety injection tank in real time and outputting effective temperature and pressure measurement signals specifically comprises the steps of:

installing a temperature and pressure monitoring instrument which is arranged redundantly in the safety injection box so as to acquire temperature and pressure of an air space in the safety injection box in real time to generate temperature and pressure measurement signals;

and checking the electrical validity of the temperature and pressure measurement signals according to a preset measurement range, identifying the measurement signals within the measurement range as valid, and identifying the measurement signals exceeding the measurement range as invalid.

10. The method of claim 7, further comprising:

establishing an isolation valve driving module to be connected with the isolation valve of the safety injection box, receiving the signal through the isolation valve driving module, and driving the isolation valve of the safety injection box to be closed according to the automatic isolation signal;

establishing a manual control switch to be connected with the isolating valve driving module, receiving a manual control signal output by the manual control switch through the isolating valve driving module, and driving the isolating valve of the safety injection tank to be opened or closed according to the manual control signal; the manual control signal has a higher priority than the automatic isolation signal.

Technical Field

The invention relates to the technical field of specially-designed safety facilities of a nuclear power plant, in particular to an automatic isolation system and method for a safety injection tank of a pressurized water reactor nuclear power plant.

Background

The pressurized water reactor nuclear power plant is provided with a safety injection system as a special safety facility, and comprises an active injection subsystem consisting of a safety injection pump and an injection pipeline, and is generally provided with a safety injection box, wherein the safety injection box is connected with a main pipeline of a primary circuit through a connecting pipeline, and the connecting pipeline is provided with an isolation valve and a check valve. The safety injection box is internally stored with boron-containing water with certain concentration and used for injecting the boron-containing water into the reactor core in a passive mode after accidents such as a primary circuit break (LOCA) and the like so as to submerge the reactor core again, ensure the cooling of the reactor core and prevent the fuel damage of the reactor core. Under accidents such as LOCA, a primary loop coolant runs off through a break, when primary loop pressure drops to below the pressure of a safety injection box, a check valve on a connecting pipeline is automatically opened, the safety injection box starts to inject boron-containing water into a reactor core, after the primary loop is completely injected into water storage in the safety injection box, the safety injection box is emptied, at the moment, an isolation valve on the connecting pipeline needs to be closed, and the safety injection box is isolated to prevent nitrogen from being injected into the primary loop. If nitrogen is injected into the primary circuit, the safety of the core will be adversely affected.

At present, the isolation operation after the safety injection tank is emptied after an accident is mostly manually performed by an operator, and whether the safety injection tank is emptied is judged according to the pressure reduction level of the safety injection tank. The method comprises the following steps that firstly, the injection process of a safety injection box after an accident is regarded as the isothermal expansion process of gas (nitrogen in the safety injection box), and the pressure of the safety injection box during evacuation is determined according to the isothermal expansion process, so that the nitrogen cannot be injected into a primary circuit under any working condition; in the second technical scheme, the injection process of the safety injection box after an accident is regarded as the adiabatic expansion process of gas, and the pressure of the safety injection box when the safety injection box is exhausted is determined according to the adiabatic expansion process, so that the boron-containing water in the safety injection box can be completely injected into a primary circuit under any working condition. However, in accident conditions, the injection process of the safety tank is not an isothermal or adiabatic expansion process in absolute terms, but a physical process between isothermal and adiabatic expansion, which results in: in the first technical scheme, although nitrogen is ensured not to be injected into the primary circuit under any working condition, under some working conditions, the water stored in the safety injection tank is possibly isolated without being completely emptied, which is unfavorable for the safety of the reactor core; for the second technical scheme, although the boron-containing water in the safety injection tank can be completely injected into the primary circuit under any working condition, under certain conditions, the risk that the isolation is implemented only after the nitrogen is partially injected into the primary circuit exists, and the safety of the reactor core is also unfavorable.

Disclosure of Invention

The invention provides an automatic isolation system and method for a safety injection tank of a pressurized water reactor nuclear power plant, aiming at the problems in the prior art, and the system and method are used for automatically isolating the safety injection tank when the safety injection tank is emptied under any accident condition, namely ensuring that all boron-containing water in the safety injection tank is injected into a primary circuit and nitrogen is not injected into the primary circuit, so that the safety of a reactor core is ensured and the safety level of a reactor is improved.

The technical scheme of the invention for solving the technical problems is as follows: on the one hand, provide a PWR nuclear power plant safety injection case automatic isolation system, include:

the temperature and pressure measuring module is arranged in the safety injection box and is used for acquiring the temperature and the pressure of an air space in the safety injection box in real time and outputting effective temperature and pressure measuring signals;

the control module is connected with the temperature and pressure measuring module and the safety injection tank isolating valve and used for receiving the temperature and pressure measuring signals and judging whether the safety injection tank is emptied or not according to the temperature and pressure measuring signals; if yes, an automatic isolation signal is output to control the isolation valve of the safety injection box to be automatically closed.

In the automatic isolation system for the safety injection tank of the pressurized water reactor nuclear power plant, the control module is further used for establishing an emptying threshold curve of the safety injection tank, and the emptying threshold curve of the safety injection tank is a corresponding relation between the pressure and the temperature of the safety injection tank;

the control module is further used for judging that the safety injection box is emptied when the coordinate points corresponding to the temperature and pressure measurement signals are located in the area above the safety injection box emptying threshold curve.

In the automatic isolation system for the safety injection tank of the pressurized water reactor nuclear power plant, the temperature and pressure measurement module comprises:

the temperature and pressure monitoring instruments are arranged redundantly and are arranged in the safety injection box and are used for acquiring temperature and pressure of an air space in the safety injection box in real time to generate temperature and pressure measuring signals;

and the validity checking module is connected with the temperature and pressure monitoring instrument and used for checking the electrical validity of the temperature and pressure measuring signals according to a preset measuring range, marking the measuring signals positioned in the measuring range as valid, and marking the measuring signals beyond the measuring range as invalid.

The automatic isolation system for the safety injection tank of the pressurized water reactor nuclear power plant further comprises: the isolation valve driving module is connected with the control module and the safety injection box isolation valve and is used for receiving and driving the safety injection box isolation valve to close according to the automatic isolation signal;

the isolation valve driving module is also connected with a manual control switch and used for receiving a manual control signal output by the manual control switch and driving the isolation valve of the safety injection box to be opened or closed according to the manual control signal; the manual control signal has a higher priority than the automatic isolation signal.

The automatic isolation system of the safety injection tank of the pressurized water reactor nuclear power plant further comprises a mode selection module which is connected with the isolation valve driving module, and the mode selection module is also connected with a test and bypass switch and is used for controlling the isolation valve driving module to isolate the automatic isolation signal according to an operation instruction output by the test and bypass switch.

In the automatic isolation system of the safety injection tank of the pressurized water reactor nuclear power plant, the control module is also used for giving an alarm indication when the automatic isolation signal is output;

and the control module is also used for not performing emptying judgment on the safety injection tank when each temperature measurement signal or each pressure measurement signal is identified to be invalid, and giving a system fault indication.

On the other hand, the automatic isolation method of the safety injection tank of the pressurized water reactor nuclear power plant is also provided, and comprises the following steps:

collecting the temperature and pressure of the air space in the safety injection box in real time, and outputting effective temperature and pressure measurement signals;

receiving the temperature and pressure measurement signals, and judging whether the safety injection tank is emptied or not according to the temperature and pressure measurement signals; if yes, an automatic isolation signal is output to control the isolation valve of the safety injection box to be automatically closed.

The automatic isolation method for the safety injection tank of the pressurized water reactor nuclear power plant further comprises the following steps:

establishing a safety injection box emptying threshold curve, wherein the safety injection box emptying threshold curve is a corresponding relation between the pressure and the temperature of a safety injection box;

and when the coordinate points corresponding to the temperature and pressure measurement signals are located in the area above the safety injection tank emptying threshold curve, judging that the safety injection tank is emptied.

In the automatic isolation method for the safety injection tank of the pressurized water reactor nuclear power plant, the temperature and the pressure of the air space in the safety injection tank are collected in real time, and effective temperature and pressure measurement signals are output, and the method specifically comprises the following steps:

installing a temperature and pressure monitoring instrument which is arranged redundantly in the safety injection box so as to acquire temperature and pressure of an air space in the safety injection box in real time to generate temperature and pressure measurement signals;

and checking the electrical validity of the temperature and pressure measurement signals according to a preset measurement range, identifying the measurement signals within the measurement range as valid, and identifying the measurement signals exceeding the measurement range as invalid.

The automatic isolation method for the safety injection tank of the pressurized water reactor nuclear power plant further comprises the following steps:

establishing an isolation valve driving module to be connected with the isolation valve of the safety injection box, receiving the signal through the isolation valve driving module, and driving the isolation valve of the safety injection box to be closed according to the automatic isolation signal;

establishing a manual control switch to be connected with the isolating valve driving module, receiving a manual control signal output by the manual control switch through the isolating valve driving module, and driving the isolating valve of the safety injection tank to be opened or closed according to the manual control signal; the manual control signal has a higher priority than the automatic isolation signal.

The implementation of the automatic isolation system and the method for the safety injection tank of the pressurized water reactor nuclear power plant provided by the invention has the following beneficial effects: the invention judges whether the safety injection tank is emptied according to the temperature and the pressure of the gas space in the safety injection tank acquired in real time, and drives the safety injection tank isolation valve on the connecting pipeline to automatically close when the safety injection tank is judged to be emptied, thereby realizing the purpose of automatic isolation of the safety injection tank, and further realizing the automatic isolation of the safety injection tank when the safety injection tank is emptied under any accident condition, thereby ensuring that the boron-containing water in the safety injection tank is completely injected into a loop and nitrogen is not injected into the loop, ensuring the safety of a reactor core and improving the safety level of a reactor; meanwhile, the technical scheme provided by the invention does not need to change the body structure of the safety injection box, is easy for engineering realization and is convenient for daily maintenance and overhaul.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic block diagram of an automatic isolation system for a safety injection tank according to an embodiment of the present invention;

FIG. 2 is an exemplary graph of a purge threshold curve for a safety tank provided by an embodiment of the present invention;

FIG. 3 is another schematic block diagram of an automatic isolation system for a safety injection tank according to an embodiment of the present invention;

fig. 4 is a flowchart of an automatic isolation method for a safety injection tank according to an embodiment of the present invention.

Detailed Description

In order that those skilled in the art will more clearly understand the present invention, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

The invention provides an automatic isolation system and method for a safety injection tank of a pressurized water reactor nuclear power plant, aiming at the problems that in the prior art, the isolation operation after the safety injection tank is emptied after an accident is mostly performed manually by an operator, so that the risk is brought to the reactor core safety, and the like, and the core idea is as follows: whether the safety injection box is emptied is judged according to the pressure and the temperature of the gas space in the safety injection box which are monitored in real time, the safety injection box is automatically isolated when the safety injection box is monitored to be emptied, automatic isolation after the safety injection box is emptied after an accident is realized, nitrogen in the safety injection box is prevented from being injected into a loop, and the safety level of a nuclear power plant is improved.

Fig. 1 is a schematic block diagram of an automatic isolation system of a safety injection tank according to an embodiment of the present invention, and as shown in fig. 1, the automatic isolation system includes a temperature and pressure measurement module 10 and a control module 20, where the temperature and pressure measurement module 10 is installed in a safety injection tank 40 and is configured to collect temperature and pressure of an air space in the safety injection tank in real time and output effective temperature and pressure measurement signals; the control module 20 is connected with the temperature and pressure measuring module 10 and the safety injection tank isolation valve 30, and is used for receiving the temperature and pressure measuring signals and judging whether the safety injection tank 40 is emptied or not according to the temperature and pressure signals; if yes, an automatic isolation signal is output to control the isolation valve 30 of the safety injection box to be automatically closed, so that the automatic isolation of the safety injection box is realized, and nitrogen injection is prevented.

Fig. 2 is an exemplary diagram of an evacuation threshold curve of the safety injection tank provided in this embodiment, and in combination with fig. 2, the control module 20 is further configured to establish an evacuation threshold curve of the safety injection tank, where the evacuation threshold curve of the safety injection tank is a corresponding relationship between pressure and temperature of the safety injection tank under a normal working condition; the control module 20 is further configured to determine that the safety injection tank is already empty when the coordinate point corresponding to the temperature and pressure measurement signal is located in the upper area of the safety injection tank empty threshold curve. And if the coordinate point corresponding to the temperature and pressure measurement signal is located in the area below the safety injection tank emptying threshold curve, the safety injection tank is not completely emptied, and the safety injection tank isolation valve does not need to be closed.

In this embodiment, the horizontal axis of the safety injection tank emptying threshold curve is a safety injection tank temperature value, the vertical axis is a safety injection tank pressure value, and the safety injection tank emptying threshold curve is determined according to the formula (1):

in the formula (1), V1 is the volume of nitrogen in the safety injection box under the normal working condition; v2 is the total volume of the safety injection box; t1 is the temperature in the safety injection box under the normal working condition; p1 is the pressure in the safety injection box under the normal working condition; p and T are the real-time pressure and temperature in the safety injection box respectively; the temperature is given in degrees centigrade and the pressure is given in MPa.

Fig. 3 is another schematic diagram of a module of the automatic isolation system of the safety injection tank provided in this embodiment, and as shown in fig. 3, the temperature and pressure measurement module 10 includes a temperature and pressure monitoring instrument 11 and an effectiveness verification module 12, where the temperature and pressure monitoring instrument 11 is provided in redundant configuration and respectively installed in the safety injection tank 40 for acquiring temperature and pressure generation temperature and pressure measurement signals of an air space in the safety injection tank in real time; the validity checking module 12 is connected to the temperature and pressure monitoring instrument 11, and is configured to check electrical validity of the temperature and pressure measurement signals according to a preset measurement range, identify the measurement signals exceeding the measurement range as invalid, and identify the measurement signals within the measurement range as valid. The temperature and pressure monitoring instruments 11 are all arranged redundantly, so that the isolation of the safety injection box is prevented from being triggered by mistake when a single instrument measuring channel is in fault, and the reliability of the system is improved.

In this embodiment, the number of the temperature and pressure monitoring meters 11 is two, taking the two measured temperature measurement signals as an example, the validity check module 12 is further configured to calculate an average value of the two temperature measurement signals as the temperature measurement signal finally output by the temperature and pressure measurement module 10 when the two temperature measurement signals are both valid; the validity check module 12 is further configured to directly use the measurement signal as a finally output temperature measurement signal when only one of the two temperature measurement signals is valid; if both measurement signals are invalid, the control module 20 directly gives an indication of a system fault. The pressure measurement signals measured by the two pressure monitoring instruments are the same, and the description is omitted here.

Further, the automatic isolation system further comprises an isolation valve driving module 50, wherein the isolation valve driving module 50 is connected with the control module 20 and the safety injection box isolation valve 30, and is used for receiving and driving the safety injection box isolation valve 30 to close according to the automatic isolation signal; the isolation valve driving module 50 is further connected with a manual control switch 60, and is used for receiving a manual control signal output by the manual control switch 60 and driving the isolation valve 30 of the safety injection tank to be opened or closed according to the manual control signal; the isolation valve drive module 50 sets the manual control signal to have a higher priority than the automatic isolation signal. The isolation valve driving module 50 provides an interface for driving the safety injection tank isolation valve 30 to operate, and can receive an automatic isolation signal and a manual control signal, and control the safety injection tank isolation valve 30 through the manual control switch 60 when necessary, for example, the isolation of the safety injection tank can be released under certain working conditions, so that the nitrogen temperature in the safety injection tank is used as a primary loop pressure, and when the manual control signal drives the safety injection tank isolation valve 30 to open, the safety injection tank automatic isolation signal is bypassed.

The automatic isolation system further comprises a mode selection module 70, the mode selection module 70 is connected with the isolation valve driving module 50, and the mode selection module 70 is further connected with a test and bypass switch 80 and is used for controlling the isolation valve driving module 50 to isolate the automatic isolation signal according to an operation instruction output by the test and bypass switch.

Under some special conditions, nitrogen in the safety injection box is required to be used for stabilizing the pressure of the primary loop, the test and bypass switch 80 provides an operation inlet capable of exiting the automatic isolation function of the safety injection box when necessary, the mode selection module 70 provides an interface for the test or bypass automatic isolation function of the safety injection box, the automatic isolation function of the safety injection box can be bypassed under the conditions of carrying out periodic tests or other situations without the automatic isolation function of the safety injection box, and the safety injection box isolation valve 30 does not receive the automatic isolation signal generated by the control module any more after bypassing.

Further, the control module 20 is further configured to give an alarm indication when outputting the automatic isolation signal; the control module 20 is further configured to, when each of the temperature measurement signals or each of the pressure measurement signals is identified as invalid, not perform evacuation judgment of the safety injection tank any more, and give a system fault indication. The alarm indication and the system fault indication are both given in the master control room, and an operator is reminded of emergency treatment in time.

In this embodiment, when the two redundant temperature measurement signals are identified as invalid or the two pressure measurement signals are identified as invalid, the control module 20 gives a system fault indication, and does not perform the above-mentioned judgment on whether the safety injection tank is empty, so as to ensure the accuracy of the result and prevent erroneous judgment.

Fig. 4 is a flowchart of an automatic isolation method for a safety injection tank according to an embodiment of the present invention, which is shown in fig. 1 to 4, and includes the steps of:

s1, collecting the temperature and the pressure of the air space in the safety injection box in real time, and outputting effective temperature and pressure measurement signals;

s2, receiving the temperature and pressure measurement signals, and judging whether the safety injection tank 40 is emptied or not according to the temperature and pressure measurement signals; if yes, an automatic isolation signal is output to control the isolation valve 30 of the safety injection tank to be automatically closed.

According to the automatic isolation method of the safety injection box, whether the safety injection box is emptied or not is judged by monitoring the temperature and the pressure of the air space in the safety injection box, and if the safety injection box is emptied, the isolation valve of the safety injection box is driven to be automatically closed, so that the safety injection box is automatically isolated.

Further, the step S2 specifically includes:

establishing a safety injection box emptying threshold curve, wherein the safety injection box emptying threshold curve is a corresponding relation between the pressure and the temperature of a safety injection box;

and when the coordinate points corresponding to the temperature and pressure measurement signals are located in the area above the safety injection tank emptying threshold curve, judging that the safety injection tank is emptied.

The step S1 specifically includes:

a temperature and pressure monitoring instrument 11 which is arranged redundantly is arranged in the safety injection box 40 so as to acquire temperature and pressure of an air space in the safety injection box in real time to generate temperature and pressure measurement signals;

and checking the electrical validity of the temperature and pressure measurement signals according to a preset measurement range, identifying the measurement signals within the measurement range as valid, and identifying the measurement signals exceeding the measurement range as invalid.

Further, the automatic isolation method further includes, before step S1, the steps of:

s10, establishing an isolation valve driving module 50 to be connected with the safety injection box isolation valve 30, receiving the signal through the isolation valve driving module 50, and driving the safety injection box isolation valve 30 to close according to the automatic isolation signal;

establishing a manual control switch 60 to be connected with an isolation valve driving module 50, receiving a manual control signal output by the manual control switch 60 through the isolation valve driving module 50, and driving an isolation valve 30 of the safety injection tank to be opened or closed according to the manual control signal; the manual control signal has a higher priority than the automatic isolation signal.

It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific process of the automatic isolation valve of the safety injection tank may refer to the implementation process corresponding to the automatic isolation system of the safety injection tank, and is not described herein again.

In conclusion, the invention provides an automatic isolation system and method for a safety injection tank of a pressurized water reactor nuclear power plant, which judges whether the safety injection tank is emptied according to the temperature and the pressure of the gas space in the safety injection tank acquired in real time, and drives an isolation valve of the safety injection tank on a connecting pipeline to be automatically closed when the safety injection tank is judged to be emptied, so that the aim of automatically isolating the safety injection tank is fulfilled, the safety injection tank can be automatically isolated when the safety injection tank is emptied under any accident condition, the boron-containing water in the safety injection tank is ensured to be completely injected into a primary circuit, the nitrogen is ensured not to be injected into the primary circuit, the safety of a reactor core is ensured, and the safety level of the reactor is improved; meanwhile, the technical scheme provided by the invention does not need to change the body structure of the safety injection box, is easy for engineering realization and is convenient for daily maintenance and overhaul.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.