Pressurized water reactor control method and device, computer device and storage medium

Abstract

The application relates to a pressurized water reactor control method, device, computer equipment and storage medium. The method comprises the following steps: when the pressurized water reactor has a dilution operation condition, performing dilution operation on the pressurized water reactor according to a first dilution flow; continuously monitoring the boron concentration of a primary coolant of the pressurized water reactor, and continuously monitoring the neutron count rate reciprocal value of the pressurized water reactor through a source range channel of the pressurized water reactor; during the dilution operation, adjusting the first dilution flow at least once according to the reduction degree of the boron concentration of the primary coolant and the neutron count rate reciprocal value; if the boron concentration of the primary coolant meets a first preset condition, stopping the dilution operation; and if the boron concentration of the primary coolant meets a second preset condition, selecting an operation mode of the pressurized water reactor according to the neutron count rate reciprocal value. The method can improve the control efficiency of the pressurized water reactor and reduce the risk of accidental criticality.

Description

Technical Field

[0001] This application relates to the field of critical start-up of pressurized water reactor nuclear power units, and in particular to a pressurized water reactor control method, apparatus, computer equipment, storage medium and computer program product. Background Technology

[0002] During the dilution operation of a PWR (Pressurized Water Reactor), the reciprocal of the SRC (Source Range Channel) neutron count rate often needs to be manually calculated by the experimenter after reading the value from the monitoring system. Both the manual data reading and calculation process take time. Once the reciprocal of the SRC neutron count rate is manually determined to have dropped to 0.10, the physics experimenter issues a stop-dilution command to the operator. Upon receiving this command, the operator uses remote control components to stop the dilution. Skilled personnel typically need 2–5 minutes to complete this process. During this process, dilution continues, according to a 10m... 3 ·h -1 Based on the estimated dilution flow rate, the dilution water volume in 2 minutes is approximately 0.333 m³. 3 The dilution volume in 5 minutes is approximately 0.833 m³. 3 Based on practical experience, after dilution is stopped and the boron concentration in the primary coolant is homogenized, the reciprocal of the SRC neutron count rate will decrease to 0.04–0.07. As the reactor approaches criticality, the neutron flux rate exhibits an exponential growth pattern. If the test personnel misjudge the timing of stopping dilution, especially if there is a delay in the appropriate time to stop dilution, it could potentially lead to unexpected criticality during the dilution process or during the homogenization of the boron concentration in the primary coolant after dilution has ceased.

[0003] The traditional method of manually calculating the reciprocal of the SRC neutron count rate to determine the point at which to stop dilution has a time lag defect, which may lead to excessive dilution, resulting in events such as accidental reactor criticality and excessively short neutron flux doubling period. This method also results in low control efficiency and a high risk of accidental criticality in pressurized water reactors. Summary of the Invention

[0004] Therefore, it is necessary to provide a pressurized water reactor control method, apparatus, computer equipment, computer-readable storage medium, and computer program product that can improve the control efficiency of pressurized water reactors and reduce the risk of accidental criticality, in order to address the above-mentioned technical problems.

[0005] In a first aspect, this application provides a method for controlling a pressurized water reactor. The method includes:

[0006] The pressurized water reactor is diluted according to the first dilution flow when the pressurized water reactor has a dilution operation condition;

[0007] The boron concentration of the primary coolant of the pressurized water reactor is continuously monitored, and the reciprocal value of the neutron count rate of the pressurized water reactor is continuously monitored through the source range channel of the pressurized water reactor;

[0008] During the dilution operation, the first dilution flow is adjusted at least once according to the decrease of the boron concentration of the primary coolant and the reciprocal value of the neutron count rate;

[0009] If the boron concentration of the primary coolant meets the first preset condition, the dilution operation is stopped, and if the boron concentration of the primary coolant meets the second preset condition, the operation mode of the pressurized water reactor is selected according to the reciprocal value of the neutron count rate.

[0010] In one embodiment, the reciprocal value of the neutron count rate of the pressurized water reactor is continuously monitored through the source range channel of the pressurized water reactor, comprising:

[0011] When the boron concentration of the primary coolant is greater than the reference concentration threshold, the first reference neutron count rate is obtained through the source range channel of the pressurized water reactor; the real-time neutron count rate of the pressurized water reactor is continuously monitored through the source range channel of the pressurized water reactor, and the reciprocal value of the neutron count rate is continuously calculated according to the real-time neutron count rate and the first reference neutron count rate;

[0012] When the boron concentration of the primary coolant is not greater than the reference concentration threshold, the dilution operation is stopped, the second reference neutron count rate is obtained through the source range channel of the pressurized water reactor; the dilution operation is continued, the real-time neutron count rate of the pressurized water reactor is continuously monitored through the source range channel of the pressurized water reactor, and the reciprocal value of the neutron count rate is continuously calculated according to the real-time neutron count rate and the second reference neutron count rate.

[0013] In one embodiment, during the dilution operation, the first dilution flow is adjusted at least once according to the decrease of the boron concentration of the primary coolant and the reciprocal value of the neutron count rate, comprising:

[0014] If the boron concentration of the primary coolant decreases to the first concentration threshold, the first dilution flow is reduced to obtain the second dilution flow;

[0015] If the reciprocal value of the neutron count rate is not less than the first reciprocal threshold, the dilution operation of the pressurized water reactor is continued according to the second dilution flow.

[0016] In one embodiment, the method further comprises:

[0017] If the reciprocal value of the neutron count rate is less than the first reciprocal threshold, the dilution operation of the pressurized water reactor is continued according to the second dilution flow, and the reciprocal value of the neutron count rate is continuously obtained.

[0018] If the neutron count rate reciprocal value is not greater than a second reciprocal threshold value, the second dilution flow rate is reduced to obtain a third dilution flow rate; the second reciprocal threshold value is less than the first reciprocal threshold value;

[0019] The dilution operation is continued on the pressurized water reactor according to the third dilution flow rate.

[0020] In one of the embodiments, if the primary coolant boron concentration meets a first preset condition, the dilution operation is stopped, and if the primary coolant boron concentration meets a second preset condition, an operation mode of the pressurized water reactor is selected according to the neutron count rate reciprocal value, including:

[0021] If the difference between the primary coolant boron concentration and the theoretical critical boron concentration of the pressurized water reactor is not greater than a second concentration threshold value, the dilution operation is stopped;

[0022] The primary coolant boron concentration is homogenized, and if the change amplitude of the primary coolant boron concentration within a preset time length is not greater than an amplitude threshold value, whether the pressurized water reactor reaches a critical state is judged according to the neutron count rate reciprocal value;

[0023] If the pressurized water reactor reaches the critical state, the temperature control rod is controlled to stabilize the core neutron flux of the pressurized water reactor.

[0024] In one of the embodiments, the method further includes:

[0025] If the neutron count rate reciprocal value is not greater than a third reciprocal threshold value, the dilution operation is stopped; the third reciprocal threshold value is less than the second reciprocal threshold value.

[0026] In one of the embodiments, whether the pressurized water reactor reaches the critical state is judged according to the neutron count rate reciprocal value, including:

[0027] If the neutron count rate reciprocal value is less than a fourth reciprocal threshold value, it is judged that the pressurized water reactor reaches the critical state;

[0028] If the neutron count rate reciprocal value is not less than the fourth reciprocal threshold value, it is judged that the pressurized water reactor does not reach the critical state;

[0029] The fourth reciprocal threshold value is less than the third reciprocal threshold value.

[0030] In one of the embodiments, the method further includes:

[0031] If the pressurized water reactor does not reach the critical state, the temperature control rod is lifted to a top position of the core at least once, and each time the temperature control rod is lifted by a preset step number;

[0032] During the lifting of the temperature control rod, whether the pressurized water reactor reaches the critical state during the lifting of the temperature control rod is continuously judged according to the neutron count rate reciprocal value;

[0033] If the pressurized water reactor reaches a critical state during the temperature control rod lifting process, the temperature control rod is controlled to stabilize the neutron flux in the core of the pressurized water reactor.

[0034] In one of the embodiments, the method further comprises:

[0035] If the pressurized water reactor does not reach a critical state during the temperature control rod lifting process, the temperature control rod is controlled to be inserted to a theoretical critical rod position.

[0036] The pressurized water reactor is subjected to a preset volume of deionized water for a supplementary dilution operation, and the step of returning to waiting for the boron concentration homogenization of the primary coolant is returned.

[0037] In a second aspect, the application further provides a pressurized water reactor control device. The device comprises:

[0038] A dilution module is configured to perform a dilution operation on the pressurized water reactor according to a first dilution flow rate when the pressurized water reactor has a dilution operation condition.

[0039] A monitoring module is configured to continuously monitor the boron concentration of the primary coolant of the pressurized water reactor, and continuously monitor the reciprocal value of the neutron count rate of the pressurized water reactor through a source range channel of the pressurized water reactor.

[0040] An adjusting module is configured to adjust the first dilution flow rate at least once during the dilution operation according to the degree of reduction of the boron concentration of the primary coolant and the reciprocal value of the neutron count rate.

[0041] A control module is configured to stop the dilution operation if the boron concentration of the primary coolant meets a first preset condition, and select an operation mode of the pressurized water reactor according to the reciprocal value of the neutron count rate if the boron concentration of the primary coolant meets a second preset condition.

[0042] In a third aspect, the application further provides a computer device. The computer device comprises a memory and a processor, the memory stores a computer program, and the processor implements the following steps when executing the computer program:

[0043] When the pressurized water reactor has a dilution operation condition, a dilution operation is performed on the pressurized water reactor according to a first dilution flow rate.

[0044] The boron concentration of the primary coolant of the pressurized water reactor is continuously monitored, and the reciprocal value of the neutron count rate of the pressurized water reactor is continuously monitored through a source range channel of the pressurized water reactor.

[0045] During the dilution operation, the first dilution flow rate is adjusted at least once according to the degree of reduction of the boron concentration of the primary coolant and the reciprocal value of the neutron count rate.

[0046] If the boron concentration of the primary coolant meets the first preset condition, the dilution operation is stopped, and if the boron concentration of the primary coolant meets the second preset condition, the operation mode of the pressurized water reactor is selected according to the reciprocal value of the neutron count rate.

[0047] In a fourth aspect, the present application further provides a computer readable storage medium. The computer readable storage medium has a computer program stored thereon, and the computer program, when executed by a processor, implements the following steps:

[0048] When the pressurized water reactor has a dilution operation condition, performing a dilution operation on the pressurized water reactor according to a first dilution flow rate;

[0049] Continuously monitoring the boron concentration of the primary coolant of the pressurized water reactor, and continuously monitoring the reciprocal value of the neutron count rate of the pressurized water reactor through a source range channel of the pressurized water reactor;

[0050] During the dilution operation, adjusting the first dilution flow rate at least once according to the degree of reduction of the boron concentration of the primary coolant and the reciprocal value of the neutron count rate;

[0051] If the boron concentration of the primary coolant meets the first preset condition, the dilution operation is stopped, and if the boron concentration of the primary coolant meets the second preset condition, the operation mode of the pressurized water reactor is selected according to the reciprocal value of the neutron count rate.

[0052] In a fifth aspect, the present application further provides a computer program product. The computer program product comprises a computer program, and the computer program, when executed by a processor, implements the following steps:

[0053] When the pressurized water reactor has a dilution operation condition, performing a dilution operation on the pressurized water reactor according to a first dilution flow rate;

[0054] Continuously monitoring the boron concentration of the primary coolant of the pressurized water reactor, and continuously monitoring the reciprocal value of the neutron count rate of the pressurized water reactor through a source range channel of the pressurized water reactor;

[0055] During the dilution operation, adjusting the first dilution flow rate at least once according to the degree of reduction of the boron concentration of the primary coolant and the reciprocal value of the neutron count rate;

[0056] If the boron concentration of the primary coolant meets the first preset condition, the dilution operation is stopped, and if the boron concentration of the primary coolant meets the second preset condition, the operation mode of the pressurized water reactor is selected according to the reciprocal value of the neutron count rate.

[0057] The control method, device, computer device, storage medium and computer program product of the pressurized water reactor, in the case that the pressurized water reactor has dilution operation conditions, perform dilution operation on the pressurized water reactor according to a first dilution flow rate; continuously monitor the boron concentration of the primary coolant of the pressurized water reactor, and continuously monitor the neutron count rate reciprocal value of the pressurized water reactor through the source range channel of the pressurized water reactor; during the dilution operation, according to the decrease of the boron concentration of the primary coolant and the neutron count rate reciprocal value, at least once adjust the first dilution flow rate; if the boron concentration of the primary coolant meets the first preset condition, stop the dilution operation, and if the boron concentration of the primary coolant meets the second preset condition, according to the neutron count rate reciprocal value, select the operation mode of the pressurized water reactor. By automatically monitoring the boron concentration of the primary coolant of the pressurized water reactor and the neutron count rate reciprocal value, adjusting the flow rate of the dilution operation, and automatically performing the corresponding operation when the pressurized water reactor is critical, the control efficiency of the pressurized water reactor can be improved and the risk of accidental criticality can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 A flowchart of a pressurized water reactor control method in an embodiment is shown;

[0059] Figure 2 A flowchart of a pressurized water reactor control method in an embodiment is shown;

[0060] Figure 3 A structural diagram of a pressurized water reactor control system in an embodiment is shown;

[0061] Figure 4 A structural diagram of a pressurized water reactor control device in an embodiment is shown;

[0062] Figure 5 An internal structure diagram of a computer device in an embodiment is shown. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0064] In one embodiment, as shown in Figure 1 A pressurized water reactor control method is provided, and the present embodiment is exemplified by the method applied to a computer device. It should be understood that the computer device can be a terminal or a server. The terminal can be various industrial computers, but is not limited to this. The server can be implemented by a single server or a server cluster composed of multiple servers. The method in the present embodiment includes the following steps:

[0065] Step 102, if the PWR has the dilution operation condition, the PWR is operated according to the first dilution flow.

[0066] Optionally, by checking the loop coolant pressure, temperature, boron concentration of the PWR which is about to start the critical operation, it is determined whether the PWR has the dilution operation condition. Only if the PWR has the dilution operation condition, the dilution operation of the PWR can be started.

[0067] Specifically, before the critical operation starts, the PWR should be adjusted to the standard hot shutdown condition, the average temperature of the loop coolant of the PWR is between 289.4-294.4℃, and the fluctuation amplitude meets the critical start parameter requirement; the pressure of the loop coolant of the PWR is 15.4MPa, and the fluctuation amplitude meets the critical start parameter requirement; the boron concentration of the loop coolant of the PWR meets the critical start parameter requirement, then it is determined that the PWR has the dilution operation condition, and the PWR can be operated according to the first dilution flow. The first dilution flow can be 27m 3 ·h -1 (cubic meters / hour).

[0068] In a feasible embodiment, before the dilution operation is performed, if the PWR has the dilution operation condition, the control rod assembly should be adjusted to the target height position according to the critical start procedure. One manual shutdown test is performed to verify the availability of the PWR shutdown protection system, and after the test is qualified, the critical start can be continued. After it is checked and confirmed that the PWR has the critical start condition, the control rod assembly is adjusted to the target height position according to the critical start procedure. After the SRC neutron count rate tends to be stable, the SRC neutron count rate is recorded, which is denoted as N p . N p is taken as the reference neutron count rate before the boron concentration of the loop coolant of the PWR drops to 2200mg·kg -1 . N p is selected as the reference neutron count rate). The pressurizer pressure control is set to the automatic control mode, and as many electric heaters of the pressurizer as possible are put into operation. Any two of the three blowdown orifices of the chemical volume and control system are opened. The trend tracking monitoring graph of the boron concentration of the loop coolant of the PWR and the reciprocal of the SRC neutron count rate is established, and the boron concentration is monitored by the boron table monitoring signal of the nuclear sampling system.

[0069] Step 104, the boron concentration of the loop coolant of the PWR is continuously monitored, and the reciprocal value of the neutron count rate of the PWR is continuously monitored through the source range channel of the PWR.

[0070] Optionally, the boron concentration of the primary coolant of the PWR is continuously monitored, the real-time neutron count rate of the PWR is continuously monitored by the SRC of the PWR, and the reciprocal value of the neutron count rate of the PWR is calculated in real time according to the currently selected reference neutron count rate. The specific calculation formula is:

[0071] N r = N b / N t

[0072] In the formula: N r is the reciprocal of the neutron count rate of the SRC; N b is the reference neutron count rate, N t is the real-time neutron count rate measured by the SRC at time t after the start of the critical operation (i.e., the dilution operation).

[0073] Step 106, during the dilution operation, the first dilution flow rate is adjusted at least once according to the decrease of the boron concentration of the primary coolant and the reciprocal value of the neutron count rate.

[0074] Optionally, during the dilution operation according to the first dilution flow rate, the boron concentration of the primary coolant is continuously monitored. The boron concentration of the primary coolant is constantly changing, and in general, the boron concentration of the primary coolant is continuously decreasing. When the boron concentration of the primary coolant decreases to a first concentration threshold, the first dilution flow rate needs to be reduced to obtain a second dilution flow rate. If the reciprocal value of the SRC neutron count rate is not less than a first reciprocal threshold, the dilution operation of the PWR is continued according to the second dilution flow rate until the dilution operation is stopped. If the reciprocal value of the SRC neutron count rate is less than the first reciprocal threshold, the dilution operation of the PWR is continued according to the second dilution flow rate, and the reciprocal value of the SRC neutron count rate is continuously obtained. When the reciprocal value of the SRC neutron count rate is not greater than a second reciprocal threshold, the second dilution flow rate is reduced to obtain a third dilution flow rate, and the dilution operation of the PWR is continued according to the third dilution flow rate until the dilution operation is stopped. This is because at the same boron concentration, the greater the SRC neutron count rate, the smaller the reciprocal value of the SRC neutron count rate, and the greater the starting neutron source activity. When the starting neutron source activity is too high, the risk of accidental criticality is higher if the dilution operation continues according to the initial dilution flow rate. Therefore, adjusting the dilution flow rate according to the reciprocal value of the SRC neutron count rate can distinguish the dilution operation of the starting neutron source activity and effectively prevent the risk of accidental criticality caused by the starting neutron source activity being too high.

[0075] Step 108, if the boron concentration of the primary coolant meets the first preset condition, the dilution operation is stopped, and if the boron concentration of the primary coolant meets the second preset condition, the operation mode of the PWR is selected according to the reciprocal value of the SRC neutron count rate.

[0076] Optionally, when the boron concentration of the primary coolant decreases to a certain extent, the dilution operation is stopped, a period of time is waited, and after the boron concentration of the primary coolant is homogenized, the current reciprocal value of the SRC neutron count rate is obtained, whether the PWR reaches the critical state is judged according to the reciprocal value of the SRC neutron count rate, and the subsequent execution operation is selected based on the current state of the PWR (whether it reaches the critical state or not).

[0077] In the above-mentioned pressurized water reactor control method, when the PWR has the dilution operation condition, the PWR is subjected to the dilution operation according to the first dilution flow rate; the boron concentration of the primary coolant of the PWR is continuously monitored, and the reciprocal value of the neutron count rate of the PWR is continuously monitored by the SRC of the PWR; during the dilution operation, the first dilution flow rate is adjusted at least once according to the decrease of the boron concentration of the primary coolant and the reciprocal value of the neutron count rate of the SRC; if the boron concentration of the primary coolant meets the first preset condition, the dilution operation is stopped, and if the boron concentration of the primary coolant meets the second preset condition, the operation mode of the PWR is selected according to the reciprocal value of the neutron count rate of the SRC. By automatically monitoring the boron concentration of the primary coolant of the PWR and the reciprocal value of the neutron count rate of the SRC, adjusting the flow rate of the dilution operation, and automatically executing the corresponding operation when the PWR is critical, the control efficiency of the PWR can be improved and the risk of accidental criticality can be reduced.

[0078] In one embodiment, the reciprocal value of the neutron count rate of the pressurized water reactor is continuously monitored by the SRC of the pressurized water reactor, comprising: when the boron concentration of the primary coolant is greater than a reference concentration threshold, a first reference neutron count rate is obtained by the SRC of the pressurized water reactor; the real-time neutron count rate of the pressurized water reactor is continuously monitored by the SRC of the pressurized water reactor, and the reciprocal value of the neutron count rate is continuously calculated according to the real-time neutron count rate and the first reference neutron count rate; when the boron concentration of the primary coolant is not greater than the reference concentration threshold, the dilution operation is stopped, a second reference neutron count rate is obtained by the SRC of the pressurized water reactor; the dilution operation is continued, the real-time neutron count rate of the pressurized water reactor is continuously monitored by the SRC of the pressurized water reactor, and the reciprocal value of the neutron count rate is continuously calculated according to the real-time neutron count rate and the second reference neutron count rate.

[0079] In the above-mentioned pressurized water reactor control method, the reference concentration threshold can be configured as 2200 mg·kg -1 .

[0080] Optionally, after checking and confirming that the PWR has reached the critical start condition, the control rod assembly is adjusted to the target height position according to the critical start program again. Generally, before the dilution operation is performed, the boron concentration of the primary coolant is greater than the reference concentration threshold, after the SRC neutron count rate tends to be stable, the SRC neutron count rate is recorded as N p . pAs the boron concentration of the primary coolant decreases to 2200 mg·kg -1 The first reference neutron count rate. After starting the dilution operation, when the boron concentration of the primary coolant decreases to 2200 mg·kg -1 , the dilution operation is stopped, and the SRC neutron count rate is waited to be stable, and the SRC neutron count rate at this time is recorded as the second reference neutron count rate in the process of the pressurized water reactor approaching criticality, denoted as N b .

[0081] In this embodiment, different reference neutron count rates are selected according to different boron concentrations of the primary coolant, which can ensure that the SRC neutron count rate reciprocal value calculated continuously is more accurate.

[0082] In one embodiment, during the dilution operation, the first dilution flow rate is adjusted at least once according to the decrease of the boron concentration of the primary coolant and the SRC neutron count rate reciprocal value, including: if the boron concentration of the primary coolant decreases to a first concentration threshold, the first dilution flow rate is reduced to obtain a second dilution flow rate; if the SRC neutron count rate reciprocal value is not less than a first reciprocal threshold, the dilution operation on the pressurized water reactor is continued according to the second dilution flow rate. If the SRC neutron count rate reciprocal value is less than the first reciprocal threshold, the dilution operation on the pressurized water reactor is continued according to the second dilution flow rate, and the SRC neutron count rate reciprocal value is continuously obtained; if the SRC neutron count rate reciprocal value is not greater than a second reciprocal threshold, the second dilution flow rate is reduced to obtain a third dilution flow rate; the second reciprocal threshold is less than the first reciprocal threshold; and the dilution operation on the pressurized water reactor is continued according to the third dilution flow rate.

[0083] The first dilution flow rate can be configured as 27 m 3 ·h -1 , the second dilution flow rate can be configured as 10 m 3 ·h -1 , the third dilution flow rate can be configured as 5 m 3 ·h -1 , the first concentration threshold can be configured as 1300 mg·kg -1 , the first reciprocal threshold can be configured as 0.2, and the second reciprocal threshold can be configured as 0.15.

[0084] Optionally, the dilution operation is continued according to the flow rate of 27 m 3 ·h -1 , and the change trend of the SRC neutron count rate reciprocal value needs to be observed during the dilution operation; when the boron concentration of the primary coolant decreases to 1300 mg·kg -1 , the dilution flow rate is adjusted to 10 m 3 ·h -1Afterwards, continue to dilute. In this process, if the SRC neutron count rate reciprocal decreases to less than 0.1, immediately stop the dilution operation. By dilution, adjust the reactor to a state close to criticality, the judgment criteria is that the SRC neutron count rate reciprocal decreases to less than or equal to 0.1, or the difference between the primary coolant boron concentration and the theoretical critical boron concentration of the control rod at the theoretical critical rod position is not more than 30 mg·kg -1 If the primary coolant boron concentration decreases to 1300 mg·kg -1 , and the corresponding SRC neutron count rate reciprocal is less than 0.2, continue to dilute at a flow rate of 10 m 3 ·h -1 until the SRC neutron count rate reciprocal decreases to 0.15, and then reduce the dilution flow rate to 5 m 3 ·h -1 and continue to dilute; this step is applicable to the critical start-up of a PWR nuclear power unit with a large start-up neutron source activity.

[0085] In this embodiment, by reducing the first dilution flow rate when the primary coolant boron concentration decreases to a first concentration threshold, a second dilution flow rate is obtained; if the SRC neutron count rate reciprocal value is not less than a first reciprocal threshold, continue to dilute the pressurized water reactor at the second dilution flow rate. If the SRC neutron count rate reciprocal value is less than the first reciprocal threshold, continue to dilute the pressurized water reactor at the second dilution flow rate and continuously obtain the SRC neutron count rate reciprocal value; if the SRC neutron count rate reciprocal value is not greater than a second reciprocal threshold, reduce the second dilution flow rate to obtain a third dilution flow rate; the second reciprocal threshold is less than the first reciprocal threshold; continue to dilute the pressurized water reactor at the third dilution flow rate. Adjusting the dilution flow rate according to the SRC neutron count rate reciprocal value can distinguish the start-up neutron source activity for dilution operation, and effectively prevent the risk of accidental criticality caused by too high start-up neutron source activity.

[0086] In one embodiment, the method further comprises: if the SRC neutron count rate reciprocal value is not greater than a third reciprocal threshold, stopping the dilution operation; the third reciprocal threshold is less than the second reciprocal threshold.

[0087] The third reciprocal threshold can be configured to 0.1.

[0088] Optionally, during the entire dilution operation, if the SRC neutron count rate reciprocal decreases to less than or equal to 0.1, the dilution operation needs to be stopped immediately. This is because when the SRC neutron count rate reciprocal decreases to less than or equal to 0.1, the SRC neutron count rate has approached the neutron count rate when the PWR is critical. The SRC neutron count rate increases exponentially with the decrease of the boron concentration of the primary coolant. If the dilution operation continues, the growth rate of the SRC neutron count rate will be faster and faster under the same decrease amount of the boron concentration of the primary coolant. Therefore, there is a great risk of accidental criticality if the dilution operation continues. Therefore, the dilution operation needs to be stopped immediately.

[0089] In this embodiment, the dilution flow rate is adjusted according to the SRC neutron count rate reciprocal value, which can distinguish the start-up of the neutron source activity for dilution operation and effectively prevent the risk of accidental criticality caused by the start-up of the neutron source activity being too high.

[0090] In one embodiment, if the boron concentration of the primary coolant meets the first preset condition, the dilution operation is stopped. If the boron concentration of the primary coolant meets the second preset condition, the operation mode of the pressurized water reactor is selected according to the SRC neutron count rate reciprocal value, including: if the difference between the boron concentration of the primary coolant and the theoretical critical boron concentration of the pressurized water reactor is not greater than a second concentration threshold, the dilution operation is stopped; waiting for the boron concentration of the primary coolant to be uniform, and if the change amplitude of the boron concentration of the primary coolant within a preset time period is not greater than an amplitude threshold, judging whether the pressurized water reactor reaches a critical state according to the SRC neutron count rate reciprocal value.

[0091] In one case, if the SRC neutron count rate reciprocal value is less than a fourth reciprocal threshold, it is judged that the pressurized water reactor reaches a critical state; and the temperature control rod is controlled to stabilize the core neutron flux rate of the pressurized water reactor.

[0092] In another case, if the SRC neutron count rate reciprocal value is not less than the fourth reciprocal threshold, it is judged that the pressurized water reactor does not reach a critical state; and the fourth reciprocal threshold is less than the third reciprocal threshold. If the pressurized water reactor does not reach a critical state, the temperature control rod is lifted to the top of the core at least once, and each time the temperature control rod is lifted by a preset step. During the lifting of the temperature control rod, it is continuously judged whether the pressurized water reactor reaches a critical state according to the SRC neutron count rate reciprocal value. If the pressurized water reactor reaches a critical state during the lifting of the temperature control rod, the temperature control rod is controlled to stabilize the core neutron flux rate of the pressurized water reactor. If the pressurized water reactor does not reach a critical state during the lifting of the temperature control rod, the temperature control rod is inserted to the theoretical critical rod position; a preset volume of deionized water is used to perform a supplementary dilution operation on the pressurized water reactor, and the step of waiting for the boron concentration of the primary coolant to be uniform is returned to.

[0093] In the above embodiment, the second concentration threshold can be configured as 30 mg·kg -1, the theoretical critical boron concentration is determined based on the current nuclear fuel loading scheme of the pressurized water reactor.

[0094] Optionally, during the dilution operation, the change trend of the SRC neutron count rate reciprocal is observed, and when the SRC neutron count rate reciprocal decreases to less than or equal to 0.1, the dilution operation is stopped; when the difference between the boron concentration of the primary coolant and the theoretical critical boron concentration of the control rod at the theoretical critical rod position is not more than 30 mg·kg -1 , the dilution operation is stopped. After waiting for the boron concentration of the primary coolant to be uniform, the waiting time is not less than 15 min. After the boron concentration of the primary coolant monitored by the boron meter is stable (the change amplitude within 5 min is not more than 10 mg·kg -1 ), 2 times of chemical sampling analysis are performed on the primary coolant and the coolant in the pressurizer respectively at an interval of 5 min, and when the deviation between the chemical sampling analysis results of the boron concentration of the primary coolant and the boron concentration of the coolant in the pressurizer is not more than 20 mg·kg -1 , it is judged whether the pressurized water reactor reaches the critical state according to the SRC neutron count rate reciprocal value, and when the SRC neutron count rate reciprocal value is very small and approaches to 0, the core neutron multiplication period of the PWR is infinite, and it is considered that the pressurized water reactor has reached the critical state. The specific judgment threshold can be configured to 0.01, but is not limited to this.

[0095] Further, after the boron concentration of the primary coolant is uniform, if the reactor has not reached the critical state, an operation of lifting the temperature control rod to make the reactor critical is prepared to be performed. The reactor is forced to approach the critical state by lifting the temperature control rod by not more than 5 steps each time, and after lifting the temperature control rod each time, a time of not less than 100 s should be waited, and in this process, the monitoring value of the core neutron multiplication period should be closely observed, and when the core neutron multiplication period appears a relatively stable monitoring value in the interval of 100-300 s, it is judged that the reactor has reached a slightly supercritical state, at this time, the reactor is adjusted to the critical state by inserting the temperature control rod downward (it is recommended to insert 1 step each time) to stabilize the core neutron flux. If the reactor still does not reach the critical state after the temperature control rod is lifted to the top position of the core, the temperature control rod is inserted downward to the theoretical critical rod position, and after supplementing 1 m 3 of deionized water, the steps of "waiting for the boron concentration of the primary coolant to be uniform, and judging whether the pressurized water reactor reaches the critical state according to the SRC neutron count rate reciprocal value" are repeatedly performed until the reactor reaches the critical state.

[0096] If the difference between the boron concentration of the primary coolant and the theoretical critical boron concentration of the pressurized water reactor is not greater than the second concentration threshold, the dilution operation is stopped; the boron concentration of the primary coolant is homogenized, and if the change range of the boron concentration of the primary coolant within a preset time length is not greater than the range threshold, whether the pressurized water reactor reaches the critical state is determined according to the reciprocal value of the SRC neutron count rate. Whether the pressurized water reactor reaches the critical state determines the subsequent operation mode of controlling the pressurized water reactor. The control efficiency of the pressurized water reactor can be improved, and the risk of accidental criticality can be reduced.

[0097] In one embodiment, a pressurized water reactor control method comprises:

[0098] When the pressurized water reactor has a dilution operation condition, the pressurized water reactor is operated according to a first dilution flow rate;

[0099] The boron concentration of the primary coolant of the pressurized water reactor is continuously monitored; when the boron concentration of the primary coolant is greater than a reference concentration threshold, a first reference neutron count rate is obtained by the SRC of the pressurized water reactor; the real-time neutron count rate of the pressurized water reactor is continuously monitored by the SRC of the pressurized water reactor, and the reciprocal value of the neutron count rate is continuously calculated according to the real-time neutron count rate and the first reference neutron count rate; when the boron concentration of the primary coolant is not greater than the reference concentration threshold, the dilution operation is stopped, a second reference neutron count rate is obtained by the SRC of the pressurized water reactor; the dilution operation is continued, the real-time neutron count rate of the pressurized water reactor is continuously monitored by the SRC of the pressurized water reactor, and the reciprocal value of the neutron count rate is continuously calculated according to the real-time neutron count rate and the second reference neutron count rate.

[0100] If the boron concentration of the primary coolant decreases to a first concentration threshold, the first dilution flow rate is reduced to obtain a second dilution flow rate; if the reciprocal value of the SRC neutron count rate is not less than a first reciprocal threshold, the dilution operation of the pressurized water reactor is continued according to the second dilution flow rate. If the reciprocal value of the SRC neutron count rate is less than the first reciprocal threshold, the dilution operation of the pressurized water reactor is continued according to the second dilution flow rate, and the reciprocal value of the SRC neutron count rate is continuously obtained; if the reciprocal value of the SRC neutron count rate is not greater than a second reciprocal threshold, the second dilution flow rate is reduced to obtain a third dilution flow rate; the second reciprocal threshold is less than the first reciprocal threshold; the dilution operation of the pressurized water reactor is continued according to the third dilution flow rate.

[0101] If the reciprocal value of the SRC neutron count rate is not greater than a third reciprocal threshold, the dilution operation is stopped; the third reciprocal threshold is less than the second reciprocal threshold.

[0102] If the difference between the boron concentration of the primary coolant and the theoretical critical boron concentration of the pressurized water reactor is not greater than the second concentration threshold, the dilution operation is stopped; the boron concentration of the primary coolant is homogenized, and if the variation range of the boron concentration of the primary coolant within a preset time length is not greater than the range threshold, whether the pressurized water reactor reaches a critical state is determined according to the SRC neutron count rate reciprocal value; if the SRC neutron count rate reciprocal value is less than the fourth reciprocal threshold, it is determined that the pressurized water reactor reaches the critical state, and if the pressurized water reactor reaches the critical state, the temperature control rod is controlled to stabilize the core neutron flux rate of the pressurized water reactor. The fourth reciprocal threshold is less than the third reciprocal threshold.

[0103] If the SRC neutron count rate reciprocal value is not less than the fourth reciprocal threshold, it is determined that the pressurized water reactor does not reach the critical state, and if the pressurized water reactor does not reach the critical state, the temperature control rod is lifted to the top of the core at least once, and each time the temperature control rod is lifted by a preset step; during the lifting of the temperature control rod, whether the pressurized water reactor reaches the critical state during the lifting of the temperature control rod is determined according to the SRC neutron count rate reciprocal value; if the pressurized water reactor reaches the critical state during the lifting of the temperature control rod, the temperature control rod is controlled to stabilize the core neutron flux rate of the pressurized water reactor. If the pressurized water reactor does not reach the critical state during the lifting of the temperature control rod, the temperature control rod is inserted to the theoretical critical rod position; a preset volume of deionized water is used to perform a supplementary dilution operation on the pressurized water reactor, and the step of waiting for the boron concentration of the primary coolant to be homogenized is returned.

[0104] In one possible implementation, a pressurized water reactor control method is applied to a pressurized water reactor nuclear power unit critical start, for example, as shown in Figure 2 , which includes:

[0105] (1) Check whether the pressure, temperature, and boron concentration of the primary coolant of the PWR to be started meet the requirements of the critical start procedure, and confirm that the PWR has met the critical start conditions.

[0106] Specifically, before the critical operation starts, the PWR should be adjusted to the standard hot shutdown condition, the average temperature of the primary coolant is between 289.4-294.4°C, and the fluctuation range meets the critical start parameter requirements; the pressure of the primary coolant system is 15.4 MPa, and the fluctuation range meets the critical start parameter requirements; the boron concentration of the primary coolant meets the critical start parameter requirements.

[0107] (2) Adjust the control rod assembly to the target height position according to the critical start procedure.

[0108] Specifically, the rod group numbered SA, SB, and SC of the shutdown control rod is lifted to 225 steps; the rod group numbered SD of the shutdown control rod, the rod group numbered G1, G2, N1, and N2 of the power control rod, and the temperature control rod group numbered R are adjusted to 5 steps.

[0109] After the critical start, the shutdown control rod numbered SD is first lifted to 225 steps, and after the neutron count rate measured by SRC is stable, the neutron count rate value is recorded as the neutron count rate reference value during the rod lifting operation. The power control rod is placed in the manual control mode, and each rod group is lifted according to the preset step scheme in the order of N2, N1, G2, and G1. Every 50 steps, the neutron count rate measured by the SRC is recorded, and the SRC neutron count rate reciprocal value is calculated. After the power control rod is lifted to the nearest rod position from 225 steps, the lifting amplitude is 225 steps minus the actual rod position, and the requirement of 50 steps per time is no longer met. After the power control rod is lifted to 225 steps, the temperature control rod is manually lifted to 130 steps at a rate of 50 steps per time, and the SRC neutron count rate reciprocal value needs to be calculated during this period.

[0110] (3) Perform one manual shutdown test to verify the availability of the reactor shutdown protection system. After the test is qualified, the critical start can continue.

[0111] (4) After checking and confirming that the PWR has met the critical start conditions, the control rod assembly is adjusted to the target height position according to the critical start procedure.

[0112] (5) After waiting for the SRC neutron count rate to stabilize, record the SRC neutron count rate, denoted as N p , as the reference neutron count rate. p Before the boron concentration of the primary coolant drops to 2200 mg·kg -1 .

[0113] (6) Set the pressure control of the stabilizer to automatic control mode, and as many as possible of the electric heaters of the stabilizer are put into operation.

[0114] (7) Open any two of the three underflow orifices of the chemical volume and control system.

[0115] (8) Establish a trend tracking monitoring graph of the boron concentration of the primary coolant and the reciprocal of the SRC neutron count rate, and the boron concentration of the primary coolant is monitored by the boron table signal from the nuclear sampling system.

[0116] (9) Start the dilution operation according to the flow rate of 27 m 3 ·h -1 . During the dilution operation, the trend of the reciprocal of the SRC neutron count rate needs to be observed. If the reciprocal of the SRC neutron count rate drops to less than or equal to 0.1, the dilution operation needs to be stopped immediately.

[0117] (10) When the boron concentration of the primary coolant drops to 2200 mg·kg -1Stop the dilution operation. Wait for the SRC neutron count rate to stabilize, and record the SRC neutron count rate at this point as the baseline neutron count rate during the PWR criticality process, denoted as N. b .

[0118] (11) According to 27m 3 ·h -1 The flow rate continues to be diluted. During the dilution process, it is necessary to observe the changing trend of the reciprocal of the SRC neutron count rate; when the boron concentration of the primary coolant decreases to 1300 mg·kg⁻¹ -1 hour (1300mg·kg) -1 To adjust the boron concentration threshold from high-flow-rate dilution to medium-flow-rate dilution (as preset), the dilution flow rate was adjusted to 10 m³ / s. 3 ·h -1 Afterwards, a medium-flow dilution is performed. During this process, if the reciprocal of the SRC neutron count rate drops to less than or equal to 0.1, the dilution operation must be stopped immediately.

[0119] (12) The reactor is adjusted to a near-critical state through dilution. The criteria for judgment are that the reciprocal of the SRC neutron count rate decreases to less than or equal to 0.1, or the difference between the boron concentration of the primary coolant and the theoretical critical boron concentration at the theoretical critical rod position does not exceed 30 mg·kg⁻¹. -1 If the boron concentration in the primary coolant drops to 1300 mg / kg... -1 If the reciprocal of the SRC neutron count rate is less than 0.2, then according to 10m 3 ·h -1 The flow rate was continued to be diluted until the reciprocal of the SRC neutron count rate dropped to 0.15, and then the dilution flow rate was reduced to 5 m³ / s. 3 ·h -1 Continue the dilution process; this step is suitable for critical startup of PWR nuclear power units with high neutron source activity. During the dilution operation, carefully observe the trend of the reciprocal of the SRC neutron count rate. Stop the dilution operation when the reciprocal of the SRC neutron count rate drops to less than or equal to 0.1. The difference between the primary coolant boron concentration and the theoretical critical boron concentration at the theoretical critical rod position should not exceed 30 mg·kg⁻¹. -1 Stop the dilution process when the time is right.

[0120] Specifically, to achieve the goal of quickly and uniformly mixing the boron concentration in the primary coolant, the electric heaters of the voltage regulator should be activated as much as possible. Simultaneously, the pressure control mode of the voltage regulator should be set to automatic, and the two sets of drain orifice plates and desalination beds of the chemical and volumetric control systems should be put into operation until the absolute value of the deviation between the boron concentration in the primary coolant and the boron concentration in the voltage regulator coolant is less than 20 mg·kg⁻¹. -1 Select the rapid dilution mode, at 27m 3·h -1 The water charging flow rate begins to dilute the primary coolant of the PWR. During the dilution process, the primary coolant is sampled and analyzed every 30 minutes to check the change of boron concentration; the coolant in the pressurizer is sampled and analyzed every 1 hour to check the change of boron concentration. The deviation of boron concentration between the primary coolant and the coolant in the pressurizer is checked every 1 hour. If the absolute value of the deviation of boron concentration exceeds 300 mg·kg -1 , the dilution flow rate needs to be reduced to 10 m 3 ·h -1 before the next sampling and analysis. After the sampling and analysis again, if the absolute value of the deviation of boron concentration still exceeds 200 mg·kg -1 , the dilution is stopped until the absolute value of the deviation of boron concentration is less than 200 mg·kg -1 . When the deviation of boron concentration between the primary coolant and the theoretical boron concentration is reduced to 200 mg·kg -1 , the dilution flow rate is adjusted to 10 m 3 ·h -1 , and the dilution continues until the reciprocal value of the SRC neutron count rate approaches 0.10, and then the dilution is stopped. During the process of waiting for the boron concentration of the primary coolant to be uniform, the critical state of the reactor is analyzed by the change of the reciprocal value of the SRC neutron count rate. It needs to be noted during the dilution operation that: the theoretical critical boron concentration of the temperature control rod at step 130 is 1151 mg·kg -1 . If the boron concentration of the primary coolant has reached this value, but the reciprocal value of the SRC neutron count rate is still greater than 0.1, the dilution continues until the reciprocal value of the SRC neutron count rate is less than or equal to 0.1. In any case, when the boron concentration of the primary coolant reaches the theoretical critical boron concentration corresponding to the temperature control rod being fully inserted into the core (1079 mg·kg -1 ), in order to prevent the positive mutation of reactivity caused by continuing to raise the temperature control rod, the dilution must be stopped immediately.

[0121] (13) Wait for the boron concentration of the primary coolant to be uniform, and the waiting time is not less than 15 minutes. When the boron concentration of the primary coolant monitored by the boron meter is stable (the change within 5 minutes is not more than 10 mg·kg -1 ), the primary coolant and the coolant in the pressurizer are respectively sampled and analyzed chemically twice at an interval of 5 minutes. When the deviation of the boron concentration between the primary coolant and the coolant in the pressurizer is not more than 20 mg·kg -1 , it is judged whether the PWR has reached the critical state according to the reciprocal value of the SRC neutron count rate. When the reciprocal value of the SRC neutron count rate is very small and tends to 0, the neutron multiplication period in the core of the PWR is infinite, and it is considered that the PWR has reached the critical state. The specific judgment threshold can be but is not limited to configured as 0.01.

[0122] (14) When the boron concentration of the primary coolant is uniform, if the PWR has not reached the critical state, prepare to perform the operation of lifting the temperature control rod to make the PWR critical.

[0123] (15) Make the PWR approach the critical state by lifting the temperature control rod no more than 5 steps each time, and after each time of lifting the temperature control rod, wait for not less than 100 s, and in this process, closely monitor the monitoring value of the core neutron multiplication period, when the core neutron multiplication period appears a relatively stable monitoring value in the interval of 100-300 s, it is judged that the PWR has reached a slightly supercritical state, at this time, the core neutron flux should be stabilized by inserting the temperature control rod downward (recommended 1 step / time) to adjust the PWR to the critical state.

[0124] (16) If the PWR still does not reach the critical state after the temperature control rod is lifted to the top position of the core, insert the temperature control rod to the theoretical critical rod position, and supplement 1m 3 of deionized water to dilute, and repeat the operation contents of steps (13) and (14) until the PWR reaches the critical state.

[0125] Specifically, if the PWR does not reach the critical state after stopping dilution, the temperature control rod is lifted at an amplitude of no more than 5 steps each time. If it is found that the PWR has reached the critical state in the process of lifting the temperature control rod, stop lifting the temperature control rod, and adjust the core neutron flux with the temperature control rod to keep the PWR in a stable critical state. If the rod position of the temperature control rod has been lifted from 130 steps to 225 steps, but the PWR still does not reach the critical state, then insert the temperature control rod to 130 steps, and then inject 1m 3 of deionized water into the primary coolant system of the PWR for dilution, wait for a long enough time to make the boron concentration of the primary coolant uniform and stable, and then judge the critical state of the PWR by observing the SRC neutron count rate again, if it is still not critical, the PWR can be made critical by lifting the temperature control rod again.

[0126] In this embodiment, the large-flow dilution corresponds to dilution with the first dilution flow, the medium-flow dilution corresponds to dilution with the second dilution flow, and the small-flow dilution corresponds to dilution with the third dilution flow.

[0127] In one embodiment, a pressurized water reactor control method is applied to a pressurized water reactor control system, which can automatically draw a trend chart of the boron concentration of the primary coolant and the SRC neutron count rate during the critical start-up process, automatically generate dilution flow adjustment instructions, and stop dilution operation instructions, as shown in Figure 3 The system comprises:

[0128] A parameter acquisition module is configured to acquire the subcritical rod count rate and the boron concentration of the primary coolant.

[0129] A calculation parameter storage module is configured to store the reference subcritical rod count rate, the theoretical critical boron concentration of the temperature control rod at the theoretical critical rod position, the boron concentration difference (the difference between the boron concentration of the primary coolant and the theoretical critical boron concentration of the temperature control rod at the theoretical critical rod position, and the preset value is 30 mg·kg -1 ), the boron concentration of the primary coolant for adjusting the medium-flow dilution (the preset value is 1300 mg·kg -1 ), the reciprocal of the subcritical rod count rate for judging whether the small-flow dilution is needed (the preset value is 0.2), the reciprocal of the subcritical rod count rate for adjusting the small-flow dilution (the preset value is 0.15), and the reciprocal of the subcritical rod count rate for judging the stop of the dilution (the preset value is 0.1).

[0130] A subcritical rod count rate reciprocal calculation module is configured to calculate the reciprocal of the subcritical rod count rate.

[0131] A medium-flow dilution adjustment instruction calculation module is configured to generate a medium-flow dilution adjustment instruction when the boron concentration of the primary coolant decreases to equal to the preset boron concentration threshold for adjusting the medium-flow dilution.

[0132] A small-flow dilution adjustment instruction calculation module is configured to calculate the difference between the boron concentration of the primary coolant and the preset boron concentration of the primary coolant for adjusting the dilution flow, and trigger the small-flow dilution adjustment instruction when the difference is 0, if the critical start-up process is applicable to the small-flow dilution adjusted from the medium-flow dilution.

[0133] A critical start-up trend graph drawing module is configured to draw a critical start-up trend graph with the boron concentration of the primary coolant as the horizontal coordinate and the reciprocal of the subcritical rod count rate as the vertical coordinate.

[0134] A stop dilution operation instruction calculation module is configured to make a logical decision according to the set stop dilution operation condition, and trigger the stop dilution operation instruction when the logical decision generates a switch signal of 1.

[0135] A display terminal is configured to display the critical start-up trend graph, the dilution flow adjustment instruction, and the stop dilution operation instruction.

[0136] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0137] In this embodiment, high-flow-rate dilution is equivalent to dilution using a first dilution flow rate, medium-flow-rate dilution is equivalent to dilution using a second dilution flow rate, and low-flow-rate dilution is equivalent to dilution using a third dilution flow rate.

[0138] Based on the same inventive concept, this application also provides a pressurized water reactor control device for implementing the pressurized water reactor control method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more pressurized water reactor control device embodiments provided below can be found in the limitations of the pressurized water reactor control method described above, and will not be repeated here.

[0139] In one embodiment, such as Figure 4 As shown, a pressurized water reactor control device 400 is provided, including: a dilution module 401, a monitoring module 402, an adjustment module 403, and a control module 404, wherein:

[0140] The dilution module 401 is used to dilute the pressurized water reactor according to a first dilution flow rate when the pressurized water reactor has the conditions for dilution operation.

[0141] The monitoring module 402 is used to continuously monitor the boron concentration of the primary coolant in the pressurized water reactor and to continuously monitor the reciprocal value of the neutron count rate of the pressurized water reactor through the source range channel of the pressurized water reactor.

[0142] The adjustment module 403 is used to adjust the first dilution flow rate at least once during the dilution operation, based on the degree of decrease in the boron concentration of the primary coolant and the reciprocal of the neutron count rate.

[0143] The control module 404 is used to stop the dilution operation if the boron concentration of the primary coolant meets the first preset condition, and to select the operating mode of the pressurized water reactor based on the reciprocal value of the neutron count rate if the boron concentration of the primary coolant meets the second preset condition.

[0144] In one embodiment, the monitoring module 402 is further configured to acquire a first reference neutron count rate through the source range channel of the PWR when the boron concentration of the primary coolant is greater than the reference concentration threshold; continuously monitor the real-time neutron count rate of the PWR through the source range channel of the PWR, and continuously calculate the neutron count rate reciprocal value according to the real-time neutron count rate and the first reference neutron count rate; stop the dilution operation when the boron concentration of the primary coolant is not greater than the reference concentration threshold, acquire a second reference neutron count rate through the source range channel of the PWR; continue the dilution operation, continuously monitor the real-time neutron count rate of the PWR through the source range channel of the PWR, and continuously calculate the neutron count rate reciprocal value according to the real-time neutron count rate and the second reference neutron count rate.

[0145] In one embodiment, the adjusting module 403 is further configured to, if the boron concentration of the primary coolant decreases to a first concentration threshold, reduce the first dilution flow to obtain a second dilution flow; if the SRC neutron count rate reciprocal value is not less than a first reciprocal threshold, continue the dilution operation on the PWR according to the second dilution flow.

[0146] In one embodiment, the adjusting module 403 is further configured to, if the SRC neutron count rate reciprocal value is less than the first reciprocal threshold, continue the dilution operation on the PWR according to the second dilution flow, and continuously acquire the SRC neutron count rate reciprocal value; if the SRC neutron count rate reciprocal value is not greater than a second reciprocal threshold, reduce the second dilution flow to obtain a third dilution flow; the second reciprocal threshold is less than the first reciprocal threshold; continue the dilution operation on the PWR according to the third dilution flow.

[0147] In one embodiment, the control module 404 is further configured to, if the difference between the boron concentration of the primary coolant and the theoretical critical boron concentration of the PWR is not greater than a second concentration threshold, stop the dilution operation; wait for the boron concentration of the primary coolant to homogenize, if the change range of the boron concentration of the primary coolant is not greater than a range threshold within a preset time length, determine whether the PWR reaches a critical state according to the SRC neutron count rate reciprocal value; if the PWR reaches the critical state, control the temperature control rod to stabilize the core neutron flux of the PWR.

[0148] In one embodiment, the control module 404 is further configured to, if the SRC neutron count rate reciprocal value is not greater than a third reciprocal threshold, stop the dilution operation; the third reciprocal threshold is less than the second reciprocal threshold.

[0149] In one embodiment, the control module 404 is further configured to, if the SRC neutron count rate reciprocal value is less than a fourth reciprocal threshold, determine that the PWR reaches the critical state; if the SRC neutron count rate reciprocal value is not less than the fourth reciprocal threshold, determine that the PWR does not reach the critical state; the fourth reciprocal threshold is less than the third reciprocal threshold.

[0150] In one embodiment, the control module 404 is further configured to, if the pressurized water reactor has not reached the critical state, raise the temperature control rod to the top of the core at least once, with each raising being a preset number of steps; during the raising of the temperature control rod, continuously determine whether the pressurized water reactor has reached the critical state based on the reciprocal value of the SRC neutron count rate; if the pressurized water reactor has reached the critical state during the raising of the temperature control rod, control the temperature control rod to stabilize the core neutron flux rate of the pressurized water reactor.

[0151] In one embodiment, the control module 404 is also used to control the temperature control rod to be lowered to the theoretical critical position if the pressurized water reactor does not reach the critical state during the temperature control rod lifting process; to perform a supplementary dilution operation on the pressurized water reactor using a preset volume of deionized water; and to return to the step of waiting for the boron concentration of the primary coolant to be homogenized.

[0152] Each module in the aforementioned pressurized water reactor control device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the computer device's memory as software, so that the processor can call and execute the corresponding operations of each module.

[0153] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 5 As shown, the computer device includes a processor, memory, input / output interface, communication interface, display unit, and input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides the environment for the operation of the operating system and computer programs in the non-volatile storage media. The input / output interface is used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a pressurized water reactor control method. The display unit of the computer device is used to form a visually visible image. It can be a display screen, a projection device, or a virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the computer device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the computer device, or external keyboards, touchpads, or mice, etc.

[0154] Those skilled in the art can understand that, Figure 5 The structure shown in the figure is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0155] In one embodiment, a computer device is provided, comprising a memory and a processor, the memory storing a computer program, and the processor implementing the following steps when executing the computer program: in the case that the pressurized water reactor has a dilution operation condition, performing a dilution operation on the pressurized water reactor according to a first dilution flow rate; continuously monitoring a primary coolant boron concentration of the pressurized water reactor, and continuously monitoring a neutron count rate reciprocal value of the pressurized water reactor through a source range channel of the pressurized water reactor; during the dilution operation, adjusting the first dilution flow rate at least once according to a decrease degree of the primary coolant boron concentration and the SRC neutron count rate reciprocal value; if the primary coolant boron concentration meets a first preset condition, stopping the dilution operation, and if the primary coolant boron concentration meets a second preset condition, selecting an operation mode of the pressurized water reactor according to the SRC neutron count rate reciprocal value.

[0156] In one embodiment, the processor further implements the following steps when executing the computer program: when the primary coolant boron concentration is greater than a reference concentration threshold value, obtaining a first reference neutron count rate through the source range channel of the pressurized water reactor; continuously monitoring a real-time neutron count rate of the pressurized water reactor through the source range channel of the pressurized water reactor, and continuously calculating the neutron count rate reciprocal value according to the real-time neutron count rate and the first reference neutron count rate; when the primary coolant boron concentration is not greater than the reference concentration threshold value, stopping the dilution operation, obtaining a second reference neutron count rate through the source range channel of the pressurized water reactor; continuing the dilution operation, continuously monitoring the real-time neutron count rate of the pressurized water reactor through the source range channel of the pressurized water reactor, and continuously calculating the neutron count rate reciprocal value according to the real-time neutron count rate and the second reference neutron count rate.

[0157] In one embodiment, the processor further implements the following steps when executing the computer program: if the primary coolant boron concentration decreases to a first concentration threshold value, reducing the first dilution flow rate to obtain a second dilution flow rate; if the SRC neutron count rate reciprocal value is not less than a first reciprocal threshold value, continuing the dilution operation on the pressurized water reactor according to the second dilution flow rate.

[0158] In one embodiment, the processor, when executing the computer program, further implements the following steps: if the SRC neutron count rate reciprocal value is less than a first reciprocal threshold, continuing to dilute the pressurized water reactor according to a second dilution flow rate, and continuously obtaining the SRC neutron count rate reciprocal value; if the SRC neutron count rate reciprocal value is not greater than a second reciprocal threshold, reducing the second dilution flow rate to obtain a third dilution flow rate; the second reciprocal threshold is less than the first reciprocal threshold; and continuing to dilute the pressurized water reactor according to the third dilution flow rate.

[0159] In one embodiment, the processor, when executing the computer program, further implements the following steps: if the difference between the primary coolant boron concentration and the theoretical critical boron concentration of the pressurized water reactor is not greater than a second concentration threshold, stopping the dilution operation; waiting for the primary coolant boron concentration to homogenize, if the change in the primary coolant boron concentration within a preset time period is not greater than a change threshold, determining whether the pressurized water reactor reaches a critical state according to the SRC neutron count rate reciprocal value; and if the pressurized water reactor reaches the critical state, controlling the temperature control rod to stabilize the core neutron flux of the pressurized water reactor.

[0160] In one embodiment, the processor, when executing the computer program, further implements the following steps: if the SRC neutron count rate reciprocal value is not greater than a third reciprocal threshold, stopping the dilution operation; and the third reciprocal threshold is less than the second reciprocal threshold.

[0161] In one embodiment, the processor, when executing the computer program, further implements the following steps: if the SRC neutron count rate reciprocal value is less than a fourth reciprocal threshold, determining that the pressurized water reactor reaches a critical state; if the SRC neutron count rate reciprocal value is not less than the fourth reciprocal threshold, determining that the pressurized water reactor does not reach a critical state; and the fourth reciprocal threshold is less than the third reciprocal threshold.

[0162] In one embodiment, the processor, when executing the computer program, further implements the following steps: if the pressurized water reactor does not reach a critical state, at least once lifting the temperature control rod to a top position of the core by a preset number of steps; continuously determining whether the pressurized water reactor reaches a critical state during the lifting of the temperature control rod according to the SRC neutron count rate reciprocal value during the lifting of the temperature control rod; and if the pressurized water reactor reaches a critical state during the lifting of the temperature control rod, controlling the temperature control rod to stabilize the core neutron flux of the pressurized water reactor.

[0163] In one embodiment, the processor, when executing the computer program, further implements the following steps: if the pressurized water reactor does not reach a critical state during the lifting of the temperature control rod, controlling the temperature control rod to be inserted to a theoretical critical rod position; performing a supplementary dilution operation on the pressurized water reactor using a preset volume of deionized water, and returning to the step of waiting for the primary coolant boron concentration to homogenize.

[0164] In one embodiment, a computer readable storage medium is provided, having stored thereon a computer program, which when executed by a processor, implements the following steps: performing a dilution operation on a pressurized water reactor at a first dilution flow rate, provided that the pressurized water reactor is in a dilution operation condition; continuously monitoring a primary coolant boron concentration of the pressurized water reactor, and continuously monitoring a neutron count rate reciprocal value of the pressurized water reactor through a source range channel of the pressurized water reactor; adjusting the first dilution flow rate at least once during the dilution operation according to a decrease degree of the primary coolant boron concentration and the neutron count rate reciprocal value; stopping the dilution operation if the primary coolant boron concentration meets a first preset condition, and selecting an operation mode of the pressurized water reactor according to the neutron count rate reciprocal value if the primary coolant boron concentration meets a second preset condition.

[0165] In one embodiment, the computer program, when executed by the processor, further implements the following steps: obtaining a first reference neutron count rate through the source range channel of the pressurized water reactor when the primary coolant boron concentration is greater than a reference concentration threshold; continuously monitoring a real-time neutron count rate of the pressurized water reactor through the source range channel of the pressurized water reactor, and continuously calculating the neutron count rate reciprocal value according to the real-time neutron count rate and the first reference neutron count rate; stopping the dilution operation when the primary coolant boron concentration is not greater than the reference concentration threshold, obtaining a second reference neutron count rate through the source range channel of the pressurized water reactor; continuing the dilution operation, continuously monitoring the real-time neutron count rate of the pressurized water reactor through the source range channel of the pressurized water reactor, and continuously calculating the neutron count rate reciprocal value according to the real-time neutron count rate and the second reference neutron count rate.

[0166] In one embodiment, the computer program, when executed by the processor, further implements the following steps: if the primary coolant boron concentration decreases to a first concentration threshold, decreasing the first dilution flow rate to obtain a second dilution flow rate; continuing the dilution operation on the pressurized water reactor at the second dilution flow rate if the neutron count rate reciprocal value is not less than a first reciprocal threshold.

[0167] In one embodiment, the computer program, when executed by the processor, further implements the following steps: if the neutron count rate reciprocal value is less than the first reciprocal threshold, continuing the dilution operation on the pressurized water reactor at the second dilution flow rate, and continuously obtaining the neutron count rate reciprocal value; decreasing the second dilution flow rate to obtain a third dilution flow rate if the neutron count rate reciprocal value is not greater than a second reciprocal threshold; the second reciprocal threshold is less than the first reciprocal threshold; and continuing the dilution operation on the pressurized water reactor at the third dilution flow rate.

[0168] In an embodiment, the computer program, when executed by the processor, further implements the following steps: if the difference between the boron concentration of the primary coolant and the theoretical critical boron concentration of the pressurized water reactor is not greater than a second concentration threshold, stopping the dilution operation; waiting for the boron concentration of the primary coolant to homogenize, if the change range of the boron concentration of the primary coolant within a preset time length is not greater than a range threshold, determining whether the pressurized water reactor reaches a critical state according to the SRC neutron count rate reciprocal value; if the pressurized water reactor reaches the critical state, controlling the temperature control rod to stabilize the core neutron flux rate of the pressurized water reactor.

[0169] In an embodiment, the computer program, when executed by the processor, further implements the following steps: if the SRC neutron count rate reciprocal value is not greater than a third reciprocal threshold, stopping the dilution operation; the third reciprocal threshold is less than the second reciprocal threshold.

[0170] In an embodiment, the computer program, when executed by the processor, further implements the following steps: if the SRC neutron count rate reciprocal value is less than a fourth reciprocal threshold, determining that the pressurized water reactor reaches the critical state; if the SRC neutron count rate reciprocal value is not less than the fourth reciprocal threshold, determining that the pressurized water reactor does not reach the critical state; the fourth reciprocal threshold is less than the third reciprocal threshold.

[0171] In an embodiment, the computer program, when executed by the processor, further implements the following steps: if the pressurized water reactor does not reach the critical state, at least once, lifting the temperature control rod to a top position of the core by a preset step; continuously determining whether the pressurized water reactor reaches the critical state during the lifting process of the temperature control rod according to the SRC neutron count rate reciprocal value during the lifting process of the temperature control rod; if the pressurized water reactor reaches the critical state during the lifting process of the temperature control rod, controlling the temperature control rod to stabilize the core neutron flux rate of the pressurized water reactor.

[0172] In an embodiment, the computer program, when executed by the processor, further implements the following steps: if the pressurized water reactor does not reach the critical state during the lifting process of the temperature control rod, controlling the temperature control rod to be inserted downward to a theoretical critical rod position; performing a supplementary dilution operation on the pressurized water reactor by using a preset volume of deionized water, and returning to the step of waiting for the boron concentration of the primary coolant to homogenize.

[0173] In an embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the steps in the above method embodiments.

[0174] It should be noted that the user information (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the user or authorized by all parties, and the collection, use and processing of related data need to comply with relevant laws, regulations and standards of relevant countries and regions.

[0175] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above-mentioned embodiment methods. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without being limited thereto.

[0176] The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0177] The above-described embodiments are merely illustrative of several embodiments of the present application, and the description is relatively specific and detailed, but should not be understood as a limitation on the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A pressurized water reactor control method, characterized by, The method comprises: In the case that the primary coolant pressure, temperature and boron concentration of a pressurized water reactor all meet the respective corresponding parameter requirements, performing dilution operation on the pressurized water reactor according to a first dilution flow rate; Continuously monitoring the primary coolant boron concentration of the pressurized water reactor, and continuously monitoring the neutron count rate reciprocal value of the pressurized water reactor through a source range channel of the pressurized water reactor; Before the dilution operation is performed, and in the case that the primary coolant boron concentration is greater than a reference concentration threshold value, obtaining a first reference neutron count rate through the source range channel of the pressurized water reactor; during the dilution operation, continuously monitoring the real-time neutron count rate of the pressurized water reactor through the source range channel of the pressurized water reactor, and continuously calculating the neutron count rate reciprocal value according to the real-time neutron count rate and the first reference neutron count rate; when the primary coolant boron concentration is not greater than the reference concentration threshold value, stopping the dilution operation, and in the case that the neutron count rate of the pressurized water reactor is in a stable state, obtaining a second reference neutron count rate through the source range channel of the pressurized water reactor; after obtaining the second reference neutron count rate, continuing the dilution operation, continuously monitoring the real-time neutron count rate of the pressurized water reactor through the source range channel of the pressurized water reactor, and continuously calculating the neutron count rate reciprocal value according to the real-time neutron count rate and the second reference neutron count rate; During the dilution operation, adjusting the first dilution flow rate at least once according to the degree of reduction of the primary coolant boron concentration and the neutron count rate reciprocal value; If the primary coolant boron concentration drops to a first concentration threshold value, reducing the first dilution flow rate to obtain a second dilution flow rate; if the neutron count rate reciprocal value is not less than a first reciprocal threshold value, continuing the dilution operation on the pressurized water reactor according to the second dilution flow rate; if the neutron count rate reciprocal value is less than the first reciprocal threshold value, continuing the dilution operation on the pressurized water reactor according to the second dilution flow rate, and continuously obtaining the neutron count rate reciprocal value; if the neutron count rate reciprocal value is not greater than a second reciprocal threshold value, reducing the second dilution flow rate to obtain a third dilution flow rate; the second reciprocal threshold value is less than the first reciprocal threshold value; continuing the dilution operation on the pressurized water reactor according to the third dilution flow rate; If the primary coolant boron concentration meets a first preset condition, stopping the dilution operation, and if the primary coolant boron concentration meets a second preset condition, selecting an operation mode for controlling the pressurized water reactor according to the neutron count rate reciprocal value; If a difference between the primary coolant boron concentration and a theoretical critical boron concentration of the pressurized water reactor is not greater than a second concentration threshold, the dilution operation is stopped; the primary coolant boron concentration is homogenized, and if a variation range of the primary coolant boron concentration within a preset time length is not greater than a range threshold, it is determined whether the pressurized water reactor reaches a critical state according to the neutron count rate reciprocal value; if the pressurized water reactor reaches the critical state, a temperature control rod is controlled to stabilize a core neutron flux of the pressurized water reactor.

2. The method of claim 1, wherein, The method further comprises: If the neutron count rate reciprocal value is not greater than a third reciprocal threshold, the dilution operation is stopped; the third reciprocal threshold is less than the second reciprocal threshold.

3. The method of claim 1, wherein, The determination whether the pressurized water reactor reaches the critical state according to the neutron count rate reciprocal value comprises: If the neutron count rate reciprocal value is less than a fourth reciprocal threshold, it is determined that the pressurized water reactor reaches the critical state; If the neutron count rate reciprocal value is not less than the fourth reciprocal threshold, it is determined that the pressurized water reactor does not reach the critical state; The fourth reciprocal threshold is less than the third reciprocal threshold.

4. The method of claim 1, wherein, The method further comprises: If the pressurized water reactor does not reach the critical state, the temperature control rod is lifted to a top position of the core for at least one time, and each time the temperature control rod is lifted by a preset step number; During the temperature control rod lifting process, it is continuously determined whether the pressurized water reactor reaches the critical state according to the neutron count rate reciprocal value; If the pressurized water reactor reaches the critical state during the temperature control rod lifting process, the temperature control rod is controlled to stabilize the core neutron flux of the pressurized water reactor.

5. The method of claim 4, wherein, The method further comprises: If the pressurized water reactor does not reach the critical state during the temperature control rod lifting process, the temperature control rod is inserted to a theoretical critical rod position; A preset volume of deionized water is used to perform a supplementary dilution operation on the pressurized water reactor, and the step of waiting for the primary coolant boron concentration to be homogenized is returned.

6. A pressurized water reactor control apparatus characterized by comprising: The device comprises: A dilution module configured to perform a dilution operation on the pressurized water reactor according to a first dilution flow rate when a primary coolant pressure, a primary coolant temperature and a primary coolant boron concentration of the pressurized water reactor all meet respective parameter requirements; A monitoring module configured to continuously monitor the primary coolant boron concentration of the pressurized water reactor and continuously monitor a neutron count rate reciprocal value of the pressurized water reactor through a source range channel of the pressurized water reactor; The monitoring module is further configured to, before the dilution operation is performed and when the boron concentration of the primary coolant is greater than a reference concentration threshold, acquire a first reference neutron count rate through a source range channel of the pressurized water reactor; during the dilution operation, continuously monitor a real-time neutron count rate of the pressurized water reactor through the source range channel of the pressurized water reactor and continuously calculate the neutron count rate reciprocal value according to the real-time neutron count rate and the first reference neutron count rate; when the boron concentration of the primary coolant is not greater than the reference concentration threshold, stop the dilution operation, and when the neutron count rate of the pressurized water reactor is in a stable state, acquire a second reference neutron count rate through the source range channel of the pressurized water reactor; after the second reference neutron count rate is acquired, continue the dilution operation, continuously monitor the real-time neutron count rate of the pressurized water reactor through the source range channel of the pressurized water reactor, and continuously calculate the neutron count rate reciprocal value according to the real-time neutron count rate and the second reference neutron count rate; The adjusting module is configured to, during the dilution operation, adjust the first dilution flow rate at least once according to a decrease degree of the boron concentration of the primary coolant and the neutron count rate reciprocal value; The adjusting module is further configured to, if the boron concentration of the primary coolant decreases to a first concentration threshold, decrease the first dilution flow rate to obtain a second dilution flow rate; if the neutron count rate reciprocal value is not less than a first reciprocal threshold, continue the dilution operation on the pressurized water reactor according to the second dilution flow rate; if the neutron count rate reciprocal value is less than the first reciprocal threshold, continue the dilution operation on the pressurized water reactor according to the second dilution flow rate and continuously acquire the neutron count rate reciprocal value; if the neutron count rate reciprocal value is not greater than a second reciprocal threshold, decrease the second dilution flow rate to obtain a third dilution flow rate; the second reciprocal threshold is less than the first reciprocal threshold; and continue the dilution operation on the pressurized water reactor according to the third dilution flow rate; The control module is configured to, if the boron concentration of the primary coolant meets a first preset condition, stop the dilution operation, and if the boron concentration of the primary coolant meets a second preset condition, select an operation mode of the pressurized water reactor according to the neutron count rate reciprocal value; The control module is further configured to, if a difference between the boron concentration of the primary coolant and a theoretical critical boron concentration of the pressurized water reactor is not greater than a second concentration threshold, stop the dilution operation; wait for the boron concentration of the primary coolant to be homogenized, and if a variation amplitude of the boron concentration of the primary coolant within a preset time length is not greater than an amplitude threshold, determine whether the pressurized water reactor reaches a critical state according to the neutron count rate reciprocal value; and if the pressurized water reactor reaches the critical state, control a temperature control rod to stabilize a core neutron fluence rate of the pressurized water reactor.

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