Method and system for handling uniform boron dilution accidents in nuclear power plants

Abstract

The present invention relates to a method and system for handling uniform boron dilution accidents in nuclear power plants. The method comprises: obtaining over-temperature and over-power measured signals from a DCS instrumentation and control system, and judging whether the over-temperature and over-power measured signals meet a first preset condition; obtaining a detection signal from a neutron injection detector arranged outside the core, and judging whether the detection signal meets a second preset condition; when the over-temperature and over-power measured signals meet the first preset condition, or when the detection signal meets the second preset condition, an isolation signal is generated to isolate the dilution source through a chemical and volume control system. By implementing the technical solution of the present invention, when the unit is in operation and the control rod is in manual control mode, the automatic protection function of the accident of erroneous dilution can be realized, the response speed of the unit to the accident of erroneous dilution can be improved, the human failure caused by the operator in the process of handling the accident of erroneous dilution can be effectively reduced, and the operating safety and economy of the nuclear power plant can be greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power safety, and in particular to a method and system for handling uniform boron dilution accidents in nuclear power plants. Background Art

[0002] The main function of the chemical and volume control system is to adjust the concentration of the boron solution to control the reactivity of the reactor. However, when the chemical and volume control system or other systems fail or human errors occur, it may cause the primary loop to accidentally introduce boric acid solution or demineralized water with a lower boron concentration. These dilution sources enter the reactor through the chemical and volume control system, which may cause a boron dilution accident that triggers a reactivity out-of-control, thus posing a great threat to the safety of the reactor.

[0003] According to the speed of reactivity introduction, boron dilution accidents can be divided into two types: uniform boron dilution accidents (slow dilution accidents) and non-uniform boron dilution (fast dilution accidents). Among them, a uniform boron dilution accident means that due to sufficient mixing of boric acid solution or clear water with a lower boron concentration with the primary loop coolant before entering the core, the boron concentration of the primary loop gradually becomes uniform and decreases; a non-uniform boron dilution accident means that due to insufficient forced circulation in the primary loop, boric acid solution or clear water with a lower boron concentration accumulates in the main pump casing. When the main pump is restarted, a low boron water mass or clear water mass enters the core, causing rapid damage to the core fuel. For non-uniform boron dilution accidents, there are usually only preventive measures because the clear water or low boron water that quickly enters the core will cause local instantaneous melting of the core fuel assembly, resulting in serious consequences. Therefore, it must be avoided in design. For uniform boron dilution accidents, after clear water or low boron water enters the primary loop, it will be evenly stirred by forced circulation such as the main pump together with the primary loop coolant (boron water that meets the requirements), and the harm to the core is not as rapid as that of fast dilution, and the effect accumulates gradually. Therefore, this type of mis-dilution can be avoided by detection and intervention to prevent the deterioration of the unit state.

[0004] Currently, for uniform boron dilution accidents in nuclear power plants, detection and protection are mostly carried out when the control rods are in the automatic control mode during power operation. That is, the actual rod position value of the control rods is obtained according to the measurement signal provided by the rod control and rod position system, and it is determined whether protection is required according to the actual rod position value. However, when the control rods are in the manual control mode, since the actual rod position value of the control rods cannot be directly obtained, effective protection of the core cannot be carried out. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method and system for handling uniform boron dilution accidents in nuclear power plants in view of the technical defect that the existing mis-dilution accident cannot apply the manual control mode of control rods.

[0006] The technical solution adopted by the present invention to solve its technical problems is: to construct a method for dealing with the uniform boron dilution accident of a nuclear power plant, including:

[0007] Step S10. Obtain the measured signal of over-temperature and over-power from the DCS instrument control system, and determine whether the measured signal of over-temperature and over-power meets the first preset condition;

[0008] Step S20. Obtain the detection signal from the neutron fluence detector arranged outside the reactor core, and determine whether the detection signal meets the second preset condition;

[0009] Step S30. When the measured signal of over-temperature and over-power meets the first preset condition, or the detection signal meets the second preset condition, generate an isolation signal to isolate the dilution source through the chemical and volume control system.

[0010] Preferably, it further includes:

[0011] When the measured signal of over-temperature and over-power meets the first preset condition, or the detection signal meets the second preset condition, an indication signal is also generated, and uniform boron dilution accident indication information is output according to the indication signal.

[0012] Preferably, it further includes:

[0013] After the treatment of the uniform boron dilution accident is completed, a reset signal input by the user is received, and the chemical and volume control system is restored to the normal operation state according to the reset signal.

[0014] Preferably, the determination of whether the measured signal of over-temperature and over-power meets the first preset condition includes:

[0015] Obtain the over-temperature difference set value, and according to the over-temperature difference set value, determine whether the measured signal of over-temperature and over-power meets the preset over-temperature difference condition, and generate a first intermediate signal when the over-temperature difference condition is met;

[0016] Obtain the over-power difference set value, and according to the over-power difference set value, determine whether the measured signal of over-temperature and over-power meets the preset over-power difference condition, and generate a second intermediate signal when the over-power difference condition is met;

[0017] Perform a logical OR operation on the first intermediate signal and the second intermediate signal, and generate a third intermediate signal;

[0018] Obtain the reactor trip signal, and perform a logical NOT operation on the reactor trip signal to generate a fourth intermediate signal;

[0019] Perform a logical AND operation on the third intermediate signal and the fourth intermediate signal, and generate a first trigger signal.

[0020] Preferably, the neutron fluence rate detector includes an intermediate range neutron fluence rate detector and a power range neutron fluence rate detector; moreover,

[0021] Step S20 includes:

[0022] Step S21. Obtain a detection signal from a neutron fluence rate detector disposed outside the reactor core, obtain the current power of the reactor according to the detection signal, and determine whether the current power is less than a power threshold. If so, execute Step S22; if not, execute Step S23;

[0023] Step S22. Determine whether the detection signal of the intermediate range neutron fluence rate detector meets a preset low power condition, and generate a second trigger signal when the low power condition is met;

[0024] Step S23. Determine whether the detection signal of the power range neutron fluence rate detector meets a preset high power condition, and generate a third trigger signal when the high power condition is met.

[0025] Preferably, Step S22 includes:

[0026] Step S221. Compare the detection signal of the intermediate range neutron fluence rate detector with a first set value, and determine whether a preset first low power condition is met according to the comparison result, and generate a second trigger signal when the first low power condition is met;

[0027] Step S222. Compare the detection signal of the power range neutron fluence rate detector with a second set value, and determine whether a preset second low power condition is met according to the comparison result, and generate a fourth trigger signal when the second low power condition is met;

[0028] Step S23 includes:

[0029] Compare the detection signal of the power range neutron fluence rate detector with a third set value, and determine whether a preset high power condition is met according to the comparison result, and generate a third trigger signal when the high power condition is met, where the third set value is greater than the second set value.

[0030] Preferably, the number of the intermediate range neutron fluence rate detectors is multiple, and they are dispersedly arranged in multiple channels outside the reactor core. Moreover, Step S221 includes:

[0031] For each channel, perform: Determine whether the detection signal of each intermediate range neutron fluence rate detector in this channel is greater than the first set value, and determine whether the number of detection signals greater than the first set value in this channel is greater than a first preset value. If it is greater than the first preset value, generate a fifth intermediate signal corresponding to this channel;

[0032] Determine whether the number of channels in which the fifth intermediate signal exists among multiple channels is greater than a second preset value. If so, generate a second trigger signal.

[0033] Preferably, the number of power range neutron fluence detectors is multiple, and they are dispersedly arranged in multiple channels outside the reactor core. Moreover,

[0034] The step S222 includes:

[0035] For each channel, perform: determine whether the detection signal of each power range neutron fluence detector in this channel is greater than the second set value, and determine whether the number of detection signals greater than the second set value in this channel is greater than a third preset value. If it is greater than the third preset value, generate a sixth intermediate signal corresponding to this channel;

[0036] Determine whether the number of channels in which the sixth intermediate signal exists among multiple channels is greater than a fourth preset value. If so, generate a fourth trigger signal;

[0037] The step S223 includes:

[0038] For each channel, perform: determine whether the detection signal of each power range neutron fluence detector in this channel is greater than the third set value, and determine whether the number of detection signals greater than the third set value in this channel is greater than a third preset value. If it is greater than the third preset value, generate a seventh intermediate signal corresponding to this channel

[0039] Determine whether the number of channels in which the seventh intermediate signal exists among multiple channels is greater than a fourth preset value. If so, generate a third trigger signal.

[0040] Preferably, the step S30 includes:

[0041] Perform a logical OR operation on the first trigger signal, the second trigger signal, the third trigger signal, and the fourth trigger signal, and generate an isolation signal, and isolate the dilution source through the chemical and volume control system.

[0042] The present invention also constructs a processing system for a uniform boron dilution accident in a nuclear power plant, including:

[0043] A first judgment module, configured to obtain an over-temperature and over-power measured signal from the DCS instrument control system, and determine whether the over-temperature and over-power measured signal meets a first preset condition;

[0044] A second judgment module, configured to obtain a detection signal from a neutron fluence detector arranged outside the reactor core, and determine whether the detection signal meets a second preset condition;

[0045] The isolation signal generation module is used to generate an isolation signal when the measured overtemperature and overpower signal meets the first preset condition, or when the detection signal meets the second preset condition, so as to isolate the dilution source through the chemical and volume control system.

[0046] Preferably, it further includes:

[0047] The output module is used to generate an indication signal when the measured overtemperature and overpower signal meets the first preset condition, or when the detection signal meets the second preset condition, and output the indication information of the uniform boron dilution accident according to the indication signal.

[0048] Preferably, it further includes:

[0049] The reset module is used to receive the reset signal input by the user after the treatment of the uniform boron dilution accident, and restore the chemical and volume control system to the normal operation state according to the reset signal.

[0050] The technical solution provided by the present invention can automatically diagnose the mis-dilution accident and automatically isolate the possible dilution source according to the measured overtemperature and overpower signal and the detection signal of the neutron fluence rate detector when a mis-dilution accident (only for the uniform boron dilution accident) occurs in a nuclear power plant. Thus, the automatic protection function for the mis-dilution accident is realized when the unit is in the operating state and the control rods are in the manual control mode. Therefore, it can help the operator to complete the treatment of the mis-dilution accident, improve the response speed of the unit to the mis-dilution accident, effectively reduce the human factor failures generated during the process of the operator dealing with the mis-dilution accident, and greatly improve the operation safety and economy of the nuclear power plant. Description of the Drawings

[0051] In order to more clearly illustrate the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts. In the drawings:

[0052] Figure 1 is the flowchart of the method for dealing with the uniform boron dilution accident in a nuclear power plant according to an embodiment of the present invention;

[0053] Figure 2 is Figure 1 the flowchart of an embodiment of step S10 in

[0054] Figure 3 is Figure 1 the flowchart of an embodiment of step S20 in

[0055] Figure 4It is the logic diagram of the processing system for the uniform boron dilution accident in a nuclear power plant in an embodiment of the present invention;

[0056] Figure 5 It is the logic structure diagram of the processing system for the uniform boron dilution accident in a nuclear power plant in an embodiment of the present invention. Specific embodiments

[0057] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0058] First of all, it should be noted that when the control rod is in the manual control mode under power conditions, the chemical and volume control system cannot be automatically isolated using the measured rod position signal. For the uniform boron dilution accident in the present invention, when the accident occurs, the neutron flux in the reactor increases, the power rises, and then the temperature and pressure change. According to these state characteristics, the present invention selects the super-power ΔT, super-temperature ΔT, and neutron fluence rate signals to characterize the uniform boron dilution accident (false dilution accident) under this condition, and the instruments use corresponding instruments such as temperature, pressure, and neutron flux.

[0059] Figure 1 It is the flow chart of the processing method for the uniform boron dilution accident in a nuclear power plant in an embodiment of the present invention. The processing method of this embodiment is applicable to the uniform boron dilution accident that occurs when the control rod is in the manual control mode. Moreover, it specifically includes the following steps:

[0060] Step S10. Obtain the measured signal of super-temperature and super-power from the DCS instrument control system, and determine whether the measured signal of super-temperature and super-power meets the first preset condition;

[0061] In this step, regarding the measured signal of super-temperature and super-power, it should be noted that it comes from the DCS instrument control system of the nuclear power plant, and specifically, it is obtained by processing the temperature difference signal of the hot and cold sections of the main loop of the reactor coolant system.

[0062] Step S20. Obtain the detection signal from the neutron fluence detector arranged outside the reactor core, and determine whether the detection signal meets the second preset condition;

[0063] Step S30. When the measured signal of super-temperature and super-power meets the first preset condition, or the detection signal meets the second preset condition, generate an isolation signal to isolate the dilution source through the chemical and volume control system.

[0064] The technical solution of this embodiment relies on the advantages of computers to establish an automatic protection method for misdilution accidents (only for uniform boron dilution accidents). When a misdilution accident occurs in a nuclear power plant, based on the measured signals of overtemperature and overpower and the detection signals of neutron fluence detectors, the misdilution accident is automatically diagnosed, and the possible dilution sources are automatically isolated, so as to realize the automatic protection function for misdilution accidents in the unit operation state. Therefore, it can help the operator complete the handling of misdilution accidents, improve the response speed of the unit to misdilution accidents, effectively reduce the human factor failures generated during the operator's handling of misdilution accidents, and greatly improve the operation safety and economy of the nuclear power plant.

[0065] Further, in an alternative embodiment, the method for handling uniform boron dilution accidents in a nuclear power plant according to the present invention further includes: when the measured overtemperature and overpower signal meets a first preset condition, or when the detection signal meets a second preset condition, an indication signal is further generated, and uniform boron dilution accident indication information is output according to the indication signal. For example, the diagnosis result of the misdilution accident can be prompted through a supporting misdilution accident display interface and audible and visual alarms. In this way, it can help the operator quickly understand the current unit state.

[0066] Further, in an alternative embodiment, the method for handling uniform boron dilution accidents in a nuclear power plant according to the present invention further includes: after the handling of the uniform boron dilution accident is completed, a reset signal input by the user is received. For example, the reset signal can be received through a supporting reset button, and the chemical and volume control system is restored to the normal operation state according to the reset signal. In this embodiment, when the handling of the misdilution accident is completed, the operator can input a reset signal by triggering the reset button to restore the chemical and volume control system to the normal operation state.

[0067] Figure 2 Yes Figure 1 It is a flowchart of an embodiment of step S10. In this embodiment, when judging whether the measured overtemperature and overpower signal in step S10 meets the first preset condition, it may specifically include:

[0068] Step S11. Obtain the over-temperature difference setting value, and judge whether the measured overtemperature and overpower signal meets the preset over-temperature difference condition according to the over-temperature difference setting value, and generate a first intermediate signal when the over-temperature difference condition is met;

[0069] In this step, regarding the set value of the super temperature difference (super temperature ΔT), it is related to the following parameters: the temperature difference value at the rated thermal power, the measured average temperature value of the reactor coolant, the designed value of the average temperature of the coolant at the rated thermal power, the rotational speed value of the reactor coolant pump, the designed rotational speed value of the coolant pump, the power difference between the upper and lower halves of the reactor core, the predetermined gain and bias values, and so on. Moreover, it can be judged whether the measured signal of super temperature and super power meets the preset super temperature difference condition in the following way: comparing the measured signal of super temperature and super power with the set value of the super temperature difference. If the measured signal of super temperature and super power is greater than the set value of the super temperature difference, it is considered to meet the preset super temperature difference condition, and a first intermediate signal is generated.

[0070] Step S12. Obtain the set value of the super power difference, and judge whether the measured signal of super temperature and super power meets the preset super power difference condition according to the set value of the super power difference, and generate a second intermediate signal when the super power difference condition is met;

[0071] In this step, regarding the set value of the super power difference (super power ΔT), it is related to the following parameters: the temperature difference value at the rated thermal power, the measured average temperature value of the reactor coolant, the designed value of the average temperature of the coolant at the rated thermal power, the rotational speed value of the reactor coolant pump, the designed rotational speed value of the coolant pump, the predetermined gain and bias values (different from the gain and bias values in the set value of the super temperature difference), and so on. In addition, it should be noted that the calculation formula of the set value of the super power difference is different from that of the set value of the super temperature difference. Moreover, it can be judged whether the measured signal of super temperature and super power meets the preset super power difference condition in the following way: comparing the measured signal of super temperature and super power with the set value of the super power difference. If the measured signal of super temperature and super power is greater than the set value of the super power difference, it is considered to meet the preset super power difference condition, and a second intermediate signal is generated.

[0072] Step S13. Perform a logical OR operation on the first intermediate signal and the second intermediate signal, and generate a third intermediate signal;

[0073] Step S14. Obtain the reactor trip signal, and perform a logical NOT operation on the reactor trip signal to generate a fourth intermediate signal;

[0074] In this step, regarding the reactor trip signal of the nuclear power plant reactor, it should be noted that it is the closing / opening signal of the reactor trip breaker. Moreover, the nuclear power plant usually sets multiple pairs of reactor trip breakers. For example, four pairs. Then, if two of the four pairs of reactor trip breakers are opened, it is considered that the reactor trip signal indicates reactor trip.

[0075] Step S15. Perform a logical AND operation on the third intermediate signal and the fourth intermediate signal, and generate a first trigger signal.

[0076] In this step, it should be noted that using the fourth intermediate signal to block the first intermediate signal and the second intermediate signal can avoid the generation of the first intermediate signal and the second intermediate signal after a non-malfunction dilution accident shutdown, because: after a non-malfunction dilution accident shutdown, the fourth intermediate signal is triggered before the first intermediate signal or the second intermediate signal, and the first intermediate signal or the second intermediate signal caused by the rod drop process during shutdown will be later than the fourth intermediate signal. Therefore, the ineffective withdrawal of the nuclear power unit can be avoided, and the economy of the nuclear power plant can be further improved.

[0077] Furthermore, regarding step S10, in a specific embodiment, the measured over-temperature and over-power signals obtained from the DCS instrument control system are the measured over-temperature and over-power signals of multiple loops, that is, there are multiple measured over-temperature and over-power signals. For example, if there are four loops corresponding to four measured over-temperature and over-power signals, then the following method can be used to determine whether to generate the first intermediate signal: if at least two of the four measured over-temperature and over-power signals are greater than the over-temperature difference setting value, it is considered that the preset over-temperature difference condition is met, and the first intermediate signal is generated; otherwise, it is considered that the preset over-temperature difference condition is not met. Similarly, the following method can be used to determine whether to generate the second intermediate signal: if at least two of the four measured over-temperature and over-power signals are greater than the over-power difference setting value, it is considered that the preset over-power difference condition is met, and the second intermediate signal is generated; otherwise, it is considered that the preset over-power difference condition is not met. In this embodiment, by performing logical degradation processing (two out of four), invalid signals can be eliminated, the redundancy performance can be enhanced, and single failure can be avoided.

[0078] Figure 3 Yes Figure 1 It is a flowchart of an embodiment of step S20. In this embodiment, the neutron fluence rate detector includes an intermediate range neutron fluence rate detector and a power range neutron fluence rate detector. Moreover, step S20 may specifically include:

[0079] Step S21. Obtain a detection signal from a neutron fluence rate detector arranged outside the reactor core, obtain the current power of the reactor according to the detection signal, and determine whether the current power is less than the power threshold. If so, execute step S22; if not, execute step S23;

[0080] In this step, the power threshold is the product of the power at full load operation of the nuclear power plant (100% nuclear power) and a specific percentage. For example, the power threshold is 10% nuclear power. In addition, the current power of the reactor can be obtained according to the detection signal of the power range neutron fluence rate detector.

[0081] Step S22. Determine whether the detection signal of the intermediate range neutron fluence rate detector meets the preset low-power condition, and generate a second trigger signal when the low-power condition is met;

[0082] Step S23. Determine whether the detection signal of the power range neutron fluence rate detector meets a preset high power condition, and generate a third trigger signal when the high power condition is met.

[0083] Further, in an optional embodiment, step S22 includes:

[0084] Step S221. Compare the detection signal of the intermediate range neutron fluence rate detector with a first set value, and determine whether a preset first low power condition is met according to the comparison result, and generate a second trigger signal when the first low power condition is met;

[0085] Step S222. Compare the detection signal of the power range neutron fluence rate detector with a second set value, and determine whether a preset second low power condition is met according to the comparison result, and generate a fourth trigger signal when the second low power condition is met;

[0086] The said step S23 includes:

[0087] Compare the detection signal of the power range neutron fluence rate detector with a third set value, and determine whether a preset high power condition is met according to the comparison result, and generate a third trigger signal when the high power condition is met, wherein the third set value is greater than the second set value.

[0088] In this embodiment, there are two set values (high set value and low set value) corresponding to the detection signal of the power range neutron fluence rate detector. Moreover, when the current power of the reactor is less than the power threshold, the detection signal of the power range neutron fluence rate detector can be compared with the low set value (the second set value) to determine whether the preset second low power condition is met; when the current power of the reactor is not less than the power threshold, the detection signal of the power range neutron fluence rate detector can be compared with the high set value (the third set value) to determine whether the preset high power condition is met.

[0089] In a specific embodiment, the number of intermediate range neutron fluence rate detectors is multiple, and they are dispersedly arranged in multiple channels outside the reactor core. For example, there are a total of four channels, and three intermediate range neutron fluence rate detectors are arranged in each channel. Then, there are a total of 12 intermediate range neutron fluence rate detectors. And step S221 includes:

[0090] For each channel, the following operations are performed: determining whether the detection signal of each intermediate range neutron fluence rate detector in the channel is greater than the first set value, and determining whether the number of detection signals greater than the first set value in the channel is greater than a first preset value. If it is greater than the first preset value, a fifth intermediate signal corresponding to the channel is generated. For example, the first preset value is 2, that is, a two-out-of-three degradation logic is used to process the three comparison results in a channel;

[0091] Determining whether the number of channels with the fifth intermediate signal among multiple channels is greater than a second preset value. If so, a second trigger signal is generated. For example, the second preset value is 2, that is, a two-out-of-four degradation logic is used to process the results of four channels.

[0092] Similarly, in a specific embodiment, the number of power range neutron fluence rate detectors is multiple and they are dispersedly arranged in multiple channels outside the reactor core. For example, there are four channels in total, and three power range neutron fluence rate detectors are arranged in each channel. Then, there are 12 power range neutron fluence rate detectors in total. Moreover, step S222 includes:

[0093] For each channel, the following operations are performed: determining whether the detection signal of each power range neutron fluence rate detector in the channel is greater than the second set value, and determining whether the number of detection signals greater than the second set value in the channel is greater than a third preset value. If it is greater than the third preset value, a sixth intermediate signal corresponding to the channel is generated;

[0094] Determining whether the number of channels with the sixth intermediate signal among multiple channels is greater than a fourth preset value. If so, a fourth trigger signal is generated;

[0095] Step S223 includes:

[0096] For each channel, the following operations are performed: determining whether the detection signal of each power range neutron fluence rate detector in the channel is greater than the third set value, and determining whether the number of detection signals greater than the third set value in the channel is greater than the third preset value. If it is greater than the third preset value, a seventh intermediate signal corresponding to the channel is generated

[0097] Determining whether the number of channels with the seventh intermediate signal among multiple channels is greater than a fourth preset value. If so, a third trigger signal is generated.

[0098] In this embodiment, for example, the third preset value and the fourth preset value are both 2. Then, a two-out-of-three degradation logic is used to process the three comparison results in a channel, and a two-out-of-four degradation logic is used to process the results of four channels.

[0099] Further, in an alternative embodiment, step S30 specifically includes:

[0100] Perform a logical OR operation on the first trigger signal, the second trigger signal, the third trigger signal, and the fourth trigger signal, generate an isolation signal, and isolate the dilution source through the chemical and volume control system.

[0101] In a specific embodiment, in combination with Figure 4 , a total of four trigger signals are sent to the input terminals of the logical OR gate. Among them, the first trigger signal is generated in the following manner: after performing a logical OR operation on the first intermediate signal and the second intermediate signal, then performing a logical AND operation with the logical NOT signal of the reactor trip signal. After the four trigger signals are subjected to a logical OR operation, they are sent to an RS flip-flop, and an isolation signal and an indication signal are output. Among them, the isolation signal is sent to the chemical and volume control system to block the continuous injection of the dilution source; the indication signal is sent to the display interface for display. Moreover, this indication signal needs to be held because this signal will disappear after a short time after the reactor trip and cannot continue to indicate to the operator. By holding this signal, the occurrence of a mis-dilution accident can be prompted to the operator. In addition, after the mis-dilution accident is handled, the operator can input a reset signal and a drive command to restore to the normal operating state.

[0102] Figure 5 FIG. is the logical structure diagram of the processing system for the uniform boron dilution accident of a nuclear power plant in an embodiment of the present invention. The processing system for the uniform boron dilution accident of the nuclear power plant in this embodiment includes: a first judgment module 10, a second judgment module 20, and an isolation signal generation module 30. Among them, the first judgment module 10 is used to obtain the measured signal of overtemperature and overpower from the DCS instrument control system and judge whether the measured signal of overtemperature and overpower meets the first preset condition; the second judgment module 20 is used to obtain the detection signal from the neutron fluence rate detector arranged outside the reactor core and judge whether the detection signal meets the second preset condition; the isolation signal generation module 30 is used to generate an isolation signal when the measured signal of overtemperature and overpower meets the first preset condition, or when the detection signal meets the second preset condition, so as to isolate the dilution source through the chemical and volume control system.

[0103] Furthermore, the processing system for the uniform boron dilution accident of this embodiment further includes an output module 40 and a reset module 50. Among them, the output module 40 is used to generate an indication signal when the measured signal of overtemperature and overpower meets the first preset condition, or when the detection signal meets the second preset condition, and output the indication information of the uniform boron dilution accident according to the indication signal. The reset module 50 is used to receive the reset signal input by the user after the uniform boron dilution accident is handled, and restore the chemical and volume control system to the normal operating state according to the reset signal.

[0104] In a specific embodiment, a display interface may be configured on the LEVEL 2 of the main control room. The display interface can display dilution accidents, including indication signals and reset buttons. Moreover, it can also display which specific abnormality occurs: high superheat ΔT (abnormality when the measured signal of superheat and superpower is compared with the set value of superheat difference); high superpower ΔT (abnormality when the measured signal of superheat and superpower is compared with the set value of superpower difference); high intermediate range neutron fluence rate (abnormality when the detection signal of the intermediate range neutron fluence detector is compared with the first set value); high power range neutron fluence rate (high set value); high power range neutron fluence rate (low set value).

[0105] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A method for treating a uniform boron dilution accident in a nuclear power plant, characterized in that: include: Step S10. Obtaining an over-temperature and over-power measured signal from the DCS instrumentation and control system, and determining whether the over-temperature and over-power measured signal meets a first preset condition; Step S20. Acquire a detection signal from a neutron flux detector disposed outside the core, and determine whether the detection signal satisfies a second preset condition; Step S30. When the over-temperature and over-power measured signal meets the first preset condition, or the detection signal meets the second preset condition, an isolation signal is generated to isolate the dilution source through the chemical and volume control system; The determining whether the over-temperature and over-power measured signal meets a first preset condition includes: Obtaining an over-temperature differential setting value, and judging whether the over-temperature and over-power measured signal meets a preset over-temperature differential condition according to the over-temperature differential setting value, and generating a first intermediate signal when the over-temperature differential condition is met; Obtaining an overpower difference setting value, and judging whether the over-temperature and overpower measured signal meets a preset overpower difference condition according to the overpower difference setting value, and generating a second intermediate signal when the overpower difference condition is met; Performing a logical OR operation on the first intermediate signal and the second intermediate signal to generate a third intermediate signal; Acquire a shutdown signal, and perform a logical negation operation on the shutdown signal to generate a fourth intermediate signal; A logic AND operation is performed on the third intermediate signal and the fourth intermediate signal to generate a first trigger signal.

2. The method for handling uniform boron dilution accidents in nuclear power plants according to claim 1, characterized in that: Also includes: When the over-temperature and over-power measured signal meets the first preset condition, or the detection signal meets the second preset condition, an indication signal is further generated, and uniform boron dilution accident indication information is output according to the indication signal.

3. The method for handling uniform boron dilution accidents in nuclear power plants according to claim 1, characterized in that: Also includes: After the uniform boron dilution accident is handled, a reset signal input by a user is received, and the chemical and volume control system is restored to a normal operating state according to the reset signal.

4. The method for handling uniform boron dilution accidents in nuclear power plants according to claim 1, characterized in that: The neutron fluence detector comprises an intermediate range neutron fluence detector and a power range neutron fluence detector; and, The step S20 comprises: Step S21. Obtain a detection signal from a neutron flux detector disposed outside the core, obtain the current power of the reactor according to the detection signal, and determine whether the current power is less than a power threshold. If so, execute step S22; if not, execute step S23; Step S22. Determine whether the detection signal of the mid-range neutron flux detector meets a preset low-power condition, and generate a second trigger signal when the low-power condition is met; Step S23: Determine whether the detection signal of the sub-fluence detector in the power range meets a preset high power condition, and generate a third trigger signal when the high power condition is met.

5. The method for handling uniform boron dilution accidents in nuclear power plants according to claim 4, characterized in that: The step S22 comprises: Step S221. Compare the detection signal of the mid-range neutron flux detector with the first set value, and determine whether a preset first low-power condition is met according to the comparison result, and generate a second trigger signal when the first low-power condition is met; Step S222. Compare the detection signal of the power range neutron flux detector with the second set value, and determine whether the preset second low power condition is met according to the comparison result, and generate a fourth trigger signal when the second low power condition is met; The step S23 comprises: The detection signal of the sub-intensity detector in the power range is compared with the third set value, and it is determined whether a preset high power condition is met based on the comparison result, and a third trigger signal is generated when the high power condition is met, wherein the third set value is greater than the second set value.

6. The method for handling uniform boron dilution accidents in nuclear power plants according to claim 5, characterized in that: There are multiple intermediate range neutron flux detectors, which are dispersedly arranged in multiple channels outside the core, and step S221 includes: For each channel, the following steps are performed: determining whether the detection signal of the sub-fluence detector in each intermediate range of the channel is greater than the first set value, and determining whether the number of detection signals greater than the first set value in the channel is greater than a first preset value; if greater than the first preset value, generating a fifth intermediate signal corresponding to the channel; It is determined whether the number of channels in which the fifth intermediate signal exists among the multiple channels is greater than a second preset value; if so, a second trigger signal is generated.

7. The method for handling uniform boron dilution accidents in nuclear power plants according to claim 5, characterized in that: The number of the power range neutron flux detectors is multiple and they are dispersedly arranged in multiple channels outside the core, and, The step S222 comprises: For each channel, the following steps are performed: determining whether the detection signal of the sub-fluence detector in each power range of the channel is greater than the second set value, and determining whether the number of detection signals greater than the second set value in the channel is greater than a third preset value; if greater than the third preset value, generating a sixth intermediate signal corresponding to the channel; determining whether the number of channels in which the sixth intermediate signal exists among the plurality of channels is greater than a fourth preset value, and if so, generating a fourth trigger signal; The step S23 comprises: For each channel, the following steps are performed: determining whether the detection signal of the sub-fluence detector in each power range of the channel is greater than the third set value, and determining whether the number of detection signals greater than the third set value in the channel is greater than a third preset value; if the number is greater than the third preset value, generating a seventh intermediate signal corresponding to the channel; It is determined whether the number of channels in which the seventh intermediate signal exists among the multiple channels is greater than a fourth preset value; if so, a third trigger signal is generated.

8. The method for handling uniform boron dilution accidents in nuclear power plants according to claim 5, characterized in that: The step S30 comprises: The first trigger signal, the second trigger signal, the third trigger signal and the fourth trigger signal are subjected to a logical OR operation to generate an isolation signal, and the dilution source is isolated through a chemical and volume control system.

9. A processing system for uniform boron dilution accidents in nuclear power plants, characterized in that: include: A first judgment module is used to obtain an over-temperature and over-power measured signal from a DCS instrumentation and control system, and judge whether the over-temperature and over-power measured signal meets a first preset condition; a second judgment module, configured to obtain a detection signal from a neutron flux detector disposed outside the core, and to judge whether the detection signal satisfies a second preset condition; An isolation signal generating module, configured to generate an isolation signal when the over-temperature and over-power measured signal meets a first preset condition, or when the detection signal meets a second preset condition, so as to isolate the dilution source through a chemical and volume control system; The determining whether the over-temperature and over-power measured signal meets a first preset condition includes: Obtaining an over-temperature differential setting value, and judging whether the over-temperature and over-power measured signal meets a preset over-temperature differential condition according to the over-temperature differential setting value, and generating a first intermediate signal when the over-temperature differential condition is met; Obtaining an overpower difference setting value, and judging whether the over-temperature and overpower measured signal meets a preset overpower difference condition according to the overpower difference setting value, and generating a second intermediate signal when the overpower difference condition is met; Performing a logical OR operation on the first intermediate signal and the second intermediate signal to generate a third intermediate signal; Acquire a shutdown signal, and perform a logical negation operation on the shutdown signal to generate a fourth intermediate signal; A logic AND operation is performed on the third intermediate signal and the fourth intermediate signal to generate a first trigger signal.

10. The system for handling uniform boron dilution accidents in nuclear power plants according to claim 9, characterized in that: Also includes: The output module is used to generate an indication signal when the over-temperature and over-power measured signal meets the first preset condition, or the detection signal meets the second preset condition, and output uniform boron dilution accident indication information according to the indication signal.

11. The system for handling uniform boron dilution accidents in nuclear power plants according to claim 9, characterized in that: Also includes: The reset module is used to receive a reset signal input by a user after the uniform boron dilution accident is handled, and restore the chemical and volume control system to a normal operating state according to the reset signal.

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