A method and system for measuring critical rod position of a pressurized water reactor

Abstract

The invention relates to a pressurized water reactor critical rod position measurement method and measurement system. The measurement method comprises: obtaining a system scheme of a pressurized water reactor control rod drive system, and determining a normal operation mechanism and a step-out mechanism for a control rod lifting process in the pressurized water reactor control rod drive system; constructing a signal simulation system for simulating and outputting a drive current signal of a control rod; constructing a simulation measurement system for simulating and measuring the number of control rod travel steps in the pressurized water reactor control rod drive system; obtaining historical experience data of the pressurized water reactor control rod drive system and configuring operation rules of the signal simulation system; setting operation conditions of the signal simulation system, generating a drive current signal of the control rod based on the operation conditions and the operation rules, and the simulation measurement system performs simulation operation based on the drive current signal and outputs a detection result; repeating the previous step, and verifying the detection result. If the result meets the requirements, the simulation measurement system is connected to the actual pressurized water reactor control rod drive system for online measurement.

Description

Technical Field

[0001] The invention relates to the technical field of pressurized water reactor rod position measurement, and in particular to a pressurized water reactor critical rod position measurement method and measurement system. Background Art

[0002] During the operation of nuclear power plants, the two most important means of reactivity control are the movement of control rods and the change of boron concentration. Among them, the reactivity control mainly used for long-term and slow onset is achieved by controlling the change of boron concentration; while the reactivity control for short-term and fast onset is controlled by moving the control rods. Since the control rod control system is an open-loop control system, how to judge whether the control rod is out of step (not in the rod position required by the instruction) after a fault occurs, how to warn about the out-of-step, and how many steps are out of step are extremely important for the control of the reactor.

[0003] At present, the rod control and rod position systems used in nuclear power plants at home and abroad are mainly divided into three categories. They are rod control and rod position systems using second-generation instrumentation and control technology, rod control and rod position systems using second-generation plus technology, and rod control and rod position systems using full digital technology. The characteristics of each system are as follows:

[0004] (1) Second-generation technology: This system requires the use of a large number of components and instruments, so the system scale is relatively large and the operation and maintenance work is very heavy.

[0005] (2) Second Generation Plus Technology: This system uses both digital control technology and analog control technology. Due to the extensive application of parallel structure (redundant design scheme) in digital technology, it has high reliability. Considering the historical operating experience of nuclear power plants, the rod control and rod position system using the second generation plus technology retains the analog technology with richer experience and higher safety while using digital control technology.

[0006] (3) Third-generation technology: The system adopts digital technology, and the main current control circuit adopts embedded technology. In addition, the system also widely adopts optical fiber network technology, DCS technology and virtual instrument technology.

[0007] Compared with the previous two generations of control technology, the third generation technology benefits from the progress of digital technology and has the advantages of high detection accuracy and high efficiency. At present, the third generation technology has been widely used in foreign nuclear power plant projects, but related nuclear power plants in China still lack corresponding technical reserves. Therefore, a control rod position measurement solution using digital technology is urgently needed to improve the localization process of the third generation nuclear power technology. Summary of the invention

[0008] The object of the present invention is to provide a method and system for measuring the critical rod position of a pressurized water reactor.

[0009] To achieve the above-mentioned purpose, the present invention provides a method for measuring the critical rod position of a pressurized water reactor, comprising:

[0010] S1. Obtaining a system solution for a pressurized water reactor control rod drive system, and determining a normal operation mechanism and a step-out mechanism for a control rod lifting process in the pressurized water reactor control rod drive system based on the system solution;

[0011] S2. construct a signal simulation system for simulating the output of the drive current signal of the control rod; wherein the signal simulation system comprises: a normal signal simulation model constructed based on the normal operation mechanism, a random simulation model of the out-of-step signal constructed based on the out-of-step mechanism, and a noise simulation model;

[0012] S3. Constructing a simulation measurement system for simulating and measuring the number of control rod travel steps in the PWR control rod drive system;

[0013] S4. Acquire historical experience data of the PWR control rod drive system during historical operation, and configure the operation rules of the normal signal simulation model and the out-of-step signal random simulation model in the signal simulation system based on the historical experience data;

[0014] S5. Setting the operating conditions of the signal simulation system, the signal simulation system generates a driving current signal of the control rod based on the operating conditions and the operating rules, and the simulation measurement system performs simulation operation based on the driving current signal and outputs a detection result;

[0015] S6. Repeat step S5 and verify the multiple groups of test results obtained. If the multiple groups of test results meet the requirements, connect the simulation measurement system to the actual pressurized water reactor control rod drive system for online measurement.

[0016] According to one aspect of the present invention, in step S1, the system solution includes: a structural solution of the pressurized water reactor control rod drive system and a lifting and lowering stepping solution of the pressurized water reactor control rod drive system; wherein the structural solution includes: a drive structure for the control rod and a drive circuit for controlling the operation of the drive structure;

[0017] The driving structure comprises: a moving fixture and a fixed fixture arranged along the axial direction of the control rod, a moving fixture coil corresponding to the moving fixture, a fixed fixture coil corresponding to the fixed fixture, and a lifting coil;

[0018] Along the axial direction of the control rod and from top to bottom, the lifting coil, the moving fixture coil and the fixed fixture coil are arranged in sequence;

[0019] The driving circuit is connected to the lifting coil, the moving fixture coil and the fixed fixture coil respectively, and is used to output driving current signals to the lifting coil, the moving fixture coil and the fixed fixture coil respectively;

[0020] The lifting and lowering stepping scheme includes: a lifting action scheme and an insertion action scheme; wherein the lifting action scheme includes the operation sequence of the lifting coil, the moving clamp coil and the fixed clamp coil when lifting the control rod; and the insertion action scheme includes the operation sequence of the lifting coil, the moving clamp coil and the fixed clamp coil when inserting the control rod.

[0021] According to one aspect of the present invention, in step S1, the step of determining the normal operation mechanism and the out-of-step mechanism for the control rod lifting process in the pressurized water reactor control rod drive system based on the system solution includes:

[0022] Based on the structural scheme and the lifting and lowering stepping scheme, a signal timing of driving current signals of the lifting coil, the moving fixture coil and the fixed fixture coil in the control rod lifting and lowering control is obtained;

[0023] Determine, based on the signal timing, a change process of the driving current signal of the movable fixture coil and the fixed fixture coil under normal operating conditions as the normal operating mechanism;

[0024] Acquire signal characteristics related to the actions performed by the hooks of the mobile fixture and / or the fixed fixture during the change process;

[0025] An out-of-step signal generation rule for adjusting the position of the signal feature during the change process is constructed based on the normal operation mechanism to obtain the out-of-step mechanism.

[0026] According to one aspect of the present invention, in step S2, the normal signal simulation model includes: a first current signal model when the hook claw is not in motion, a second current signal model when the hook claw is in motion, and a third current signal model when the hook claw completes the motion;

[0027] In step S2, the step of constructing a signal simulation system for outputting a driving current signal of the control rod includes:

[0028] An equivalent circuit model of the driving circuit is constructed, and based on the equivalent circuit model, a first simulation formula for a driving current signal when the hook is not in motion and when the hook has completed motion is obtained, which is expressed as:

[0029]

[0030] A second simulation formula for the driving current signal during the hook action is constructed based on the Gaussian function, which is expressed as:

[0031]

[0032] Among them, a represents the amplitude, μ represents the offset, and σ represents the steepness;

[0033] Constructing the first current signal model and the third current signal model on a LabVIEW simulation platform based on the first simulation formula, and constructing the second current signal model on a LabVIEW simulation platform based on the second simulation formula, and connecting the first signal model, the third current signal model, and the second current signal model to form the normal signal simulation model;

[0034] Based on the out-of-step mechanism, a random simulation model of an out-of-step signal is constructed on a LabVIEW simulation platform, and an output end of the random simulation model of the out-of-step signal is connected to an input end of the normal signal simulation model;

[0035] A noise simulation model is constructed based on the LabVIEW simulation platform, and the output end of the normal signal simulation model is connected to the input end of the noise simulation model.

[0036] According to one aspect of the present invention, in step S3, the simulation measurement system includes: a measurement amplifier module for signal amplification, a filter module for filtering the signal, an analog / digital converter module for analog-to-digital conversion of the signal, a data preprocessing module for sampling and preprocessing the signal, and a signal restoration module for performing forward step statistics, out-of-step step statistics and out-of-step alarm.

[0037] According to one aspect of the present invention, in step S3, in the step of constructing a simulation measurement system for simulating and measuring the number of control rod travel steps in the pressurized water reactor control rod drive system, the simulation measurement system is constructed using a LabVIEW simulation platform.

[0038] According to one aspect of the present invention, the data preprocessing module includes: a decompression module for smoothing the signal, a convolution module for removing singular terms in the signal, a scaling module for scaling the signal, and a data output module.

[0039] According to one aspect of the present invention, the signal restoration module includes: a step number calculation module and an information output module;

[0040] The step number calculation module includes: a calculation control for calculating the number of steps of an input signal;

[0041] The information output module includes: an actual moving step count unit, a lost step count unit and a lost step warning unit;

[0042] The out-of-step warning unit is provided with a setting port for adjusting the alarm resolution.

[0043] According to one aspect of the present invention, the calculation control calculates the number of steps of the input signal based on the following steps, including:

[0044] Get all the peaks and valleys in the input signal;

[0045] Obtaining the mean of all the peaks, and obtaining the mean of all the troughs;

[0046] removing peaks smaller than the mean value among all the peaks, and removing troughs larger than the mean value among all the troughs;

[0047] Merging the adjacent peaks and troughs to generate a peak-trough cycle merged signal;

[0048] The number of peaks in the combined signal is counted to obtain the number of steps traveled.

[0049] To achieve the above-mentioned purpose of the invention, the present invention provides a measurement system constructed based on the aforementioned pressurized water reactor critical rod position measurement method, comprising: a signal simulation system and a simulation measurement system;

[0050] The signal simulation system is used to simulate and output the driving current signal of the control rod in the control rod driving system of the pressurized water reactor; wherein the signal simulation system includes: a normal signal simulation model, a random simulation model of the out-of-step signal and a noise simulation model;

[0051] The simulation measurement system is used to simulate and measure the number of travel steps of the control rods in the pressurized water reactor control rod drive system; wherein, the simulation measurement system includes: a measurement amplifier module for signal amplification, a filter module for filtering the signal, an analog / digital converter module for analog-to-digital conversion of the signal, a data preprocessing module for sampling and preprocessing the signal, and a signal restoration module for performing travel step statistics, out-of-step step statistics and out-of-step alarm.

[0052] According to a scheme of the present invention, the present invention can realize accurate judgment of control rod movement and step number by measuring coil drive current signal, which greatly reduces the complexity of the system. The measurement system of control rod out-of-step situation can be flexibly customized according to the drive current signal of different control rods, which greatly reduces the workload of staff, shortens the system construction period, saves test equipment, reduces radiation to staff, etc.

[0053] According to one scheme of the present invention, the method of the present invention can realize accurate judgment on the action of the mechanism in the control rod drive system, and further can realize the resolution positioning of the control rod position to the level of 1 step, which greatly improves the measurement accuracy, can provide accurate reference in physical experiments, and in practical applications, can effectively assist management personnel in management and reduce the operating risks of pressurized water reactors. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a flowchart schematically showing a method for measuring a critical rod position of a pressurized water reactor according to an embodiment of the present invention;

[0055] Figure 2 is a structural diagram schematically showing a driving structure according to an embodiment of the present invention;

[0056] Figure 3 is a flow chart schematically showing a step-by-step scheme of control rod lifting actions according to one embodiment of the present invention;

[0057] Figure 4 is a flow chart schematically illustrating a step-by-step scheme of control rod insertion action according to one embodiment of the present invention;

[0058] Figure 5 is a timing diagram schematically showing a driving current signal change during a boosting process according to an embodiment of the present invention;

[0059] Figure 6 is a timing diagram schematically showing a driving current signal change during an insertion process according to an embodiment of the present invention;

[0060] Figure 7 is a diagram schematically showing an actual waveform of a driving current signal during a boosting process according to an embodiment of the present invention;

[0061] Figure 8 is a diagram schematically showing an actual waveform of a driving current signal during an insertion process according to an embodiment of the present invention;

[0062] Fig. 9 is a schematic diagram showing an actual waveform enlargement of a driving current signal at a groove return stage according to an embodiment of the present invention;

[0063] Fig.10 is a continuous waveform diagram of a driving current signal schematically showing a boosting process according to an embodiment of the present invention;

[0064] Fig.11 is an equivalent circuit model diagram schematically showing a driving circuit according to an embodiment of the present invention;

[0065] Fig.12is a simulation waveform diagram schematically showing a driving current signal when an action is not completed according to an embodiment of the present invention;

[0066] Fig.13 is a simulation waveform diagram schematically showing a driving current signal during operation according to an embodiment of the present invention;

[0067] Fig.14 is a complete simulation waveform diagram schematically showing a driving current signal according to an embodiment of the present invention;

[0068] Fig.15 is a structural diagram schematically showing a signal simulation system according to an embodiment of the present invention;

[0069] Fig.16 is a structural diagram schematically showing a measurement amplifier module according to an embodiment of the present invention;

[0070] Fig.17 is a structural diagram schematically showing a filter module according to an embodiment of the present invention;

[0071] Fig.18 is a structural diagram schematically showing an analog / digital converter module according to an embodiment of the present invention;

[0072] Fig.19 is a structural diagram schematically showing a data preprocessing module according to an embodiment of the present invention;

[0073] Fig. 20 is a structural diagram schematically showing a signal restoration module according to an embodiment of the present invention;

[0074] Fig.21 is a counting flow chart schematically showing a calculation control according to an embodiment of the present invention;

[0075] Fig. 22 is a diagram schematically showing a lifting action verification process of an embodiment of the present invention;

[0076] Fig.23 is a diagram schematically showing a lifting action verification process according to another embodiment of the present invention;

[0077] Fig.24 is a diagram schematically showing a lifting action verification process according to another embodiment of the present invention;

[0078] Fig.25 is a diagram schematically showing an insertion action verification process of an embodiment of the present invention;

[0079] Fig.26is a diagram schematically showing an insertion action verification process according to another embodiment of the present invention;

[0080] Fig. 27 It is a diagram schematically showing an insertion action verification process according to another embodiment of the present invention. DETAILED DESCRIPTION

[0081] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not therefore limited to the following embodiments.

[0082] like Figure 1 As shown, according to one embodiment of the present invention, a method for measuring a critical rod position of a pressurized water reactor of the present invention comprises:

[0083] S1. Obtain a system solution for a pressurized water reactor control rod drive system, and determine a normal operation mechanism and a step-out mechanism for a control rod lifting process in the pressurized water reactor control rod drive system based on the system solution;

[0084] S2. Constructing a signal simulation system for simulating the output drive current signal of the control rod; wherein the signal simulation system includes: a normal signal simulation model constructed based on a normal operation mechanism, a random simulation model of an out-of-step signal constructed based on an out-of-step mechanism, and a noise simulation model;

[0085] S3. Construct a simulation measurement system for simulating the number of control rod travel steps in a pressurized water reactor control rod drive system;

[0086] S4. Obtain historical experience data of the control rod drive system of the pressurized water reactor during historical operation, and configure the operation rules of the normal signal simulation model and the out-of-step signal random simulation model in the signal simulation system based on the historical experience data;

[0087] S5. Setting the operating conditions of the signal simulation system, the signal simulation system generates a driving current signal of the control rod based on the operating conditions and operating rules, and the simulation measurement system performs simulation operation based on the driving current signal and outputs the detection result;

[0088] S6. Repeat step S5 and verify the multiple groups of test results obtained. If the multiple groups of test results meet the requirements, connect the simulation measurement system to the actual pressurized water reactor control rod drive system for online measurement.

[0089] According to one embodiment of the present invention, in step S1, the system scheme includes: a structural scheme of a pressurized water reactor control rod drive system and a lifting and lowering stepping scheme of the pressurized water reactor control rod drive system. In this embodiment, the structural scheme covers the overall structural composition of the pressurized water reactor control rod drive system. Specifically, the structural scheme includes: a drive structure for control rods and a drive circuit for controlling the operation of the drive structure. Since the overall structure of the pressurized water reactor control rod drive system is complex in actual applications, and many structures have a low correlation with the lifting and lowering drive process of the control rods, the relevant parts directly related to the lifting and lowering of the control rods are selected in this scheme for explanation. Furthermore, as Figure 2 As shown, the driving structure includes: a mobile fixture 1 and a fixed fixture 2 arranged along the axial direction of the control rod, a mobile fixture coil MG corresponding to the mobile fixture 1, a fixed fixture coil SG corresponding to the fixed fixture 2, and a lifting coil LC. Along the axial direction of the control rod and from top to bottom, the lifting coil LC, the mobile fixture coil MG and the fixed fixture coil SG are arranged in sequence. In this embodiment, the driving circuit is connected to the lifting coil LC, the mobile fixture coil MG and the fixed fixture coil SG, respectively, and is used to output driving current signals to the lifting coil LC, the mobile fixture coil MG and the fixed fixture coil SG, respectively.

[0090] In this embodiment, the hooks 1a of the movable fixture 1 and the hooks 2a of the fixed fixture 2 are both openable and closable and connected to notches arranged at equal intervals on the control rod, so as to achieve the fixation and movement of the control rod.

[0091] In this embodiment, the lifting and lowering stepping scheme includes: a lifting action scheme and an insertion action scheme; wherein the lifting action scheme includes the operating sequence of the lifting coil, the moving clamp coil and the fixing clamp coil when lifting the control rod; the insertion action scheme includes the operating sequence of the lifting coil, the moving clamp coil and the fixing clamp coil when inserting the control rod.

[0092] In order to further illustrate the operation process of the control rod of the present invention, the operation process is illustrated with reference to the accompanying drawings.

[0093] Combination Figure 2 and Figure 3 As shown in the figure, when the movable clamp coil MG and the fixed clamp coil SG are locked, the lifting action of the control rod is divided into 8 steps:

[0094] (1) The locking structure of the mobile fixture coil MG is disengaged;

[0095] (2) The mobile fixture coil MG is energized to close the hook of the mobile fixture;

[0096] (3) The fixing fixture coil SG is disconnected, releasing the hook of the fixing fixture;

[0097] (4) The lifting coil LC is energized to increase the lift force;

[0098] (5) The fixed clamp coil SG is energized to lock the control rod;

[0099] (6) Disconnect the hook of the mobile fixture;

[0100] (7) The lifting coil LC is powered off, and the mobile fixture coil MG and the lifting coil LC structure automatically descend;

[0101] (8) The movable fixture coil MG is energized to close the claw of the movable fixture.

[0102] During the above-mentioned lifting action, in a normally operating pressurized water reactor, only steps (3) to (7) will be repeated, while steps (1) and (2) are steps that only occur during the startup of the reactor equipment, and step (8) will only occur after the shutdown action of the reactor equipment.

[0103] Combination Figure 2 and Figure 4 As shown in FIG. 1 , the insertion action (i.e., the lowering action) of the control rod when the movable clamp coil MG and the fixed clamp coil SG are already locked is divided into 8 steps:

[0104] (1) The clamp coil MG is moved to disengage the hook of the clamp;

[0105] (2) lifting coil LC, increasing the lifting force, lifting the lifting coil LC, and moving the fixture coil MG;

[0106] (3) The mobile fixture coil MG is energized to close the hook of the mobile fixture;

[0107] (4) The fixture coil SG is de-energized to release the hook of the fixture;

[0108] (5) The lifting coil LC is powered off, the lifting coil LC, the mobile fixture coil MG and the control rod automatically descend one step (by gravity);

[0109] (6) The fixture coil SG is energized to close the hook of the fixture;

[0110] (7) The mobile fixture coil MG is powered off, releasing the hook of the mobile fixture;

[0111] (8) The mobile fixture coil MG coil is energized to close the hook of the mobile fixture.

[0112] During the above-mentioned insertion process, in a normally operating pressurized water reactor, only steps (3) to (7) will be repeated, while steps (1) and (2) are steps that will only occur during the startup of the reactor equipment, and step (8) will only occur after the shutdown of the reactor equipment.

[0113] According to an embodiment of the present invention, in step S1, the step of determining the normal operation mechanism and the out-of-step mechanism for the control rod lifting process in the control rod drive system of a pressurized water reactor based on the system solution includes:

[0114] Based on the structural scheme and the lifting and lowering stepping scheme, the signal timing of the current signal driven by the lifting coil, the mobile clamp coil and the fixed clamp coil in the control rod lifting and lowering control is obtained; in this embodiment, based on the above analysis and determination of the control rod lifting and insertion process, it can be clearly understood that during the operation of the above three coils, the current signal passed through them will change accordingly with the moving state of the control rod. Here, by detecting the change of the current signal in the three coils to generate a magnetic field of corresponding size, it can be used to monitor and control the action of the control rod. Among them, the current state in the action and stable state can be divided into zero current, low level current and high level current, and the corresponding action can be divided into three states: holding, transfer and lifting. According to the change of the current in the coil, the corresponding action of the coil can be judged during the action of the control rod.

[0115] In this embodiment, the timing sequence of the current signal change during the lifting process of the control rod can be obtained by setting the minimum speed of the control rod movement during the actual operation of the nuclear power plant to be one step every 7500ms (8 steps / m) and the maximum speed to be one step every 833ms (72 steps / m). Figure 5 Similarly, the timing of the current signal change during the insertion of the control rod can also be obtained accordingly, see Figure 6 shown.

[0116] Further, combined with Figure 7 , Figure 8 and Fig. 9 As shown, based on the signal timing obtained above, the change process of the driving current signal of the moving fixture coil and the fixed fixture coil under normal operating conditions is determined as the normal operating mechanism; in this embodiment, since the movement process of the control rod is completed by the charging and discharging sequence of the coil, the process of the coil charging and discharging to generate magnetic force is the lifting process of the control rod. Since the charging process of the coil is not an instantaneous current rise and fall, but a slow rise and fall, the hook of the moving fixture corresponding to the moving fixture coil MG and the hook of the fixed fixture corresponding to the fixed fixture coil SG in the lifting process of the control rod mainly have the following three stages:

[0117] (1) Initial power-on stage: In this stage, the coil current begins to increase. Because the coil is an inductive load, the current increases slowly. As the current slowly increases, the electromagnetic force gradually increases. When the coil current does not reach a certain level, the magnetic force is very small and does not work.

[0118] (2) Back-groove stage: When the electromagnetic force increases to a certain extent with the current, the claw moves, the current still increases, the magnetic gap above the magnet decreases, and the lifting force increases. However, when the position of the coil changes, the corresponding magnetic flux decreases, the inductance of the coil increases, resulting in a decrease in current, and a back-groove will be generated during the dynamic change of the current.

[0119] (3) End of action: After the action is completed, the position of the hook and the inductance of the coil remain unchanged, and the coil forms a temporary stable state of the loop. In this state, the current continues to rise, charging the inductive load, causing the current to rise slowly until the current stabilizes and reaches a peak value.

[0120] Furthermore, based on the charging and discharging process of the coil, signal characteristics related to the action of the hook of the mobile fixture and / or the fixed fixture during the change process can be obtained. In this embodiment, since the change in the current signal of the coil contains the action information of the control rod, the action of the control rod can be judged according to the change in the current. Based on the aforementioned charging and discharging process, it can be known that since there will be a back groove in the process of the coil current rising, the appearance of this back groove represents the completion of the action of the hook. When the action of the hook is not completed, the current signal will not produce a back groove, so the action of the coil can be judged according to whether there is back groove information.

[0121] Furthermore, based on the normal operation mechanism, a desynchronization signal generation rule is constructed to adjust the position of the signal feature during the change process to obtain the desynchronization mechanism. Fig.10 As shown, the lifting process is illustrated as an example, where Fig.10 The left side of the figure shows the waveform of the current signal in the coil when the previous signal sequence completes normal lifting (i.e., the normal operation mechanism), and the right side shows the fault waveform when the step is lost during the lifting process (i.e., the step-out mechanism). By comparison, it can be seen that in the fault waveform, the coil current does not have the small groove (i.e., the groove phase) that should appear in the process of rising from zero. This groove indicates that the hook corresponding to the coil is hooked into the control rod. Instead, it appears after a delay of a period of time (about 180ms), which means that the hook moves and hooks into the control rod at this time. Due to the large distortion of the current waveform, the control system alarm is triggered, the timing of the rod lifting is interrupted, and the control system fails. It can be seen that the delayed appearance of the small groove (i.e., the groove phase) causes the control rod to lose step, and compared with other control groups in the same group, the control rod moves one step less. Therefore, it can be known from the above process that in the normal operation mechanism, if the groove phase corresponding to the action of the clamp hook is delayed, the normal drive current signal can be converted into a step-out signal (i.e., the step-out signal generation rule), and then the normal drive current signal can be adjusted according to this rule to convert the normal operation mechanism into a step-out mechanism.

[0122] According to an embodiment of the present invention, in step S2, the normal signal simulation model includes: a first current signal model when the hook claw is not in motion, a second current signal model when the hook claw is in motion, and a third current signal model when the hook claw completes the motion;

[0123] In step S2, the step of constructing a signal simulation system for outputting a driving current signal of a control rod includes:

[0124] Construct an equivalent circuit model of the driving circuit; in this embodiment, see Fig.11 As shown in FIG. 1 , taking the mobile fixture coil as an example, since the rising process of the driving current signal for the coil is a slow rising process and there is an obvious return groove signal during the rising process, the corresponding equivalent circuit model is constructed (such as Fig.11 In this embodiment, the equivalent circuit model includes: an equivalent resistance R of the coil, an equivalent inductance L, an inverter tube VT1, a chopper tube VT2, an energy dissipation resistor R for releasing the self-induced electromotive force of the working coil 0 ;

[0125] Furthermore, the circuit equation is constructed based on the equivalent circuit model:

[0126]

[0127] Where I is the current passing through the coil;

[0128] From the above formula, we can see that since the inductance value changes as the coil moves, the inductance value is a function variable related to the displacement value x. Finally, the voltage value E on the coil is obtained through the equation between these values. At the beginning of the current rise, the position of the coil changes, that is, the L value does not change, so the above circuit equation can be transformed into:

[0129]

[0130] Based on the above simplified formula, it can be known that it is the formula for the zero-state response of inductor charging. Then, the calculation formula for the current in the coil can be derived as follows:

[0131]

[0132] Furthermore, by taking the derivative of the above current formula, the slope of the current can be obtained, which is expressed as:

[0133]

[0134] From the current slope formula, we can see that the starting slope of the current at the initial moment is E / L.

[0135] In this embodiment, since the equivalent circuit model of the coil is in the form of inductive load charging and discharging, when no displacement occurs, the inductance value remains unchanged. Therefore, the inductive charging formula can be used to establish the first simulation formula of the driving current signal when the hook is not in motion and when the hook completes the motion. In this embodiment, based on the original actual data, the initial slope E / L of the current at the initial moment can be obtained to be about 8.5. From the beginning of the current to the end of the motion, there are about 150 groups of data, and the RC value that can be designed is 60. Then, the first simulation formula is expressed as:

[0136]

[0137] Then, the current signal when the control rod action is not completed is simulated according to the first simulation formula. After simulation, the signal waveform of the incomplete action is obtained, such as Fig.12 shown.

[0138] In this embodiment, a second simulation formula for the driving current signal during hook action is constructed based on the derivative of the Gaussian function, which is expressed as:

[0139]

[0140] Among them, a represents the amplitude, μ represents the offset, and σ represents the steepness;

[0141] In this embodiment, according to the measured data, a=850, μ=90, σ=20, and then the simulation is performed based on the second simulation formula to obtain the current waveform when the hook moves in the model. The jitter signal waveform during the action is as follows: Fig.13 shown.

[0142] Based on the above simulation, the waveform of the incomplete signal and the current waveform during the action are superimposed to obtain the complete driving current signal waveform, see Fig.14 shown.

[0143] In this embodiment, if Fig.15 As shown, a first current signal model and a third current signal model are constructed on a LabVIEW simulation platform based on a first simulation formula, and a second current signal model is constructed on a LabVIEW simulation platform based on a second simulation formula, and the first signal model, the third current signal model and the second current signal model are connected to form a normal signal simulation model;

[0144] Further, such as Fig.15As shown, a random simulation model of an out-of-step signal is constructed on a LabVIEW simulation platform based on the out-of-step mechanism, and the output end of the random simulation model of the out-of-step signal is connected to the input end of the normal signal simulation model; in this embodiment, an out-of-step control end for controlling random out-of-step events is provided in the random simulation model of the out-of-step signal, and a random integer (between 0 and 50) can be configured on the out-of-step control end to control the normal signal simulation model to add an out-of-step signal after outputting a driving electrical signal of the integer number of steps.

[0145] Further, such as Fig.15 As shown, a noise simulation model is constructed based on the LabVIEW simulation platform, and the output end of the normal signal simulation model is connected to the input end of the noise simulation model. In this embodiment, the noise simulation model is constructed to add noise to the generated control rod drive current signal. In this embodiment, the amplitude of the white noise is set to 1.

[0146] Finally, if Fig.15 As shown, the out-of-step signal random simulation model, the normal signal simulation model and the noise simulation model are connected in series in sequence to obtain a signal simulation system for outputting a driving current signal. At the same time, a travel step number control terminal is set at the input end of the out-of-step signal random simulation model to set the total number of steps of the output signal of the entire signal simulation system.

[0147] According to one embodiment of the present invention, in the step of constructing a simulation measurement system for simulating and measuring the number of control rod travel steps in a pressurized water reactor control rod drive system, the simulation measurement system is constructed using a LabVIEW simulation platform. In this embodiment, the simulation measurement system is constructed using interlocking or linkage mechanisms such as control rod action, reactivity, and power temperature feedback mechanisms. In this embodiment, the simulation measurement system includes: a measurement amplifier module for signal amplification, a filter module for filtering the signal, an analog / digital converter module for analog-to-digital conversion of the signal, a data preprocessing module for sampling and preprocessing the signal, and a signal restoration module for performing statistics on the number of travel steps, statistics on the number of out-of-step steps, and out-of-step alarms.

[0148] like Fig.16 As shown, according to one embodiment of the present invention, the measurement amplifier module is implemented by calling the amplifier module provided in the LabVIEW simulation platform, and the amplification factor is set to 100 times and the offset is set to 0.

[0149] like Fig.17 As shown, according to one embodiment of the present invention, the filter module is implemented by calling the filter provided in the LabVIEW simulation platform, and its low cutoff frequency is set to 50.

[0150] like Fig.18As shown, according to one embodiment of the present invention, the analog / digital converter module is implemented by calling the analog-to-digital conversion module provided in the LabVIEW simulation platform, and the resolution is set to 16 bits.

[0151] like Fig.19 As shown, according to one embodiment of the present invention, the data preprocessing module includes: a decompression module for smoothing the signal, a convolution module for removing singular terms in the signal, a scaling module for scaling the signal, and a data output module.

[0152] like Fig. 20 As shown, according to an embodiment of the present invention, the signal restoration module includes: a step number calculation module and an information output module. In this embodiment, the step number calculation module includes: a calculation control for calculating the number of steps of the input signal; wherein the calculation control is obtained by writing in C language.

[0153] like Fig.21 As shown, according to one embodiment of the present invention, the calculation control calculates the number of steps of the input signal based on the following steps, including:

[0154] Obtain all the peaks and troughs in the input signal; in this embodiment, receive the input signal, and select three adjacent signal data (i.e., the nth signal, the n+1th signal, and the n+2th signal); determine whether the signal in the middle position (i.e., the n+1th signal) is a peak; if so, add it to the peak and trough array, if not, determine whether it is a trough, if so, add it to the peak and trough array, otherwise sequentially extract the next signal data to perform the above steps;

[0155] Get the mean of all peaks, and get the mean of all troughs;

[0156] Remove the peaks that are smaller than the mean among all the peaks, and remove the troughs that are larger than the mean among all the troughs; in this embodiment, extract the peaks from the peak and trough array obtained in the above step and compare them with the mean, if it is larger than the mean, retain it, if it is smaller than the mean, delete it from the array, similarly extract the troughs from the peak and trough array and compare them with the mean, if it is smaller than the mean, retain it, if it is larger than the mean, delete it from the array;

[0157] Adjacent peaks and troughs are merged to generate a peak-trough cycle merged signal; in this embodiment, the obtained merged signal satisfies the rule of one peak and one trough.

[0158] Count the peaks in the merged signal to get the number of steps traveled.

[0159] like Fig. 20As shown, according to an embodiment of the present invention, the information output module includes: an actual moving step number statistics unit, a step loss statistics unit and a step loss warning unit. In this embodiment, the actual moving step number statistics unit counts the steps based on the step number output of the traveling step number calculation module. In this embodiment, the step loss statistics unit is used to receive the total number of steps set in the traveling step number control unit in the signal simulation system, and the number of steps output by the traveling step number calculation module, and obtain the step loss after subtracting them. In this embodiment, the step loss warning unit is used to receive the step loss output by the step loss statistics unit and to alarm. In this embodiment, the step loss warning unit is provided with a setting port for adjusting the alarm resolution. Among them, when the step loss reaches the resolution requirement, the step loss warning unit alarms, and if the step loss does not reach the resolution requirement, the step loss warning unit does not alarm. For example, when the alarm resolution in the step loss warning unit is set to 8 steps, it is only when the step loss reaches 8 steps that it is determined as a step loss event and an alarm is issued.

[0160] According to an embodiment of the present invention, in step S4, historical experience data of the control rod drive system of a pressurized water reactor is obtained during the historical operation process, and in the step of configuring the operation rules of the normal signal simulation model and the random simulation model of the out-of-step signal in the signal simulation system based on the historical experience data, a normal and out-of-step database of the control rods of the pressurized water reactor is constructed based on the actual early operation experience of the pressurized water reactor, and the simulation work of the restoration of the control rods of the pressurized water reactor out-of-step signal system is carried out. Specifically, the random integer of the out-of-step control end in the random simulation model of the out-of-step signal of the signal simulation system is set through the obtained control rod normal and out-of-step database, so as to obtain the operation rules of the signal simulation system outputting the normal drive current signal and the out-of-step signal.

[0161] According to one embodiment of the present invention, in step S5, in the step of setting the operating conditions of the signal simulation system, the operating conditions include: setting the total number of steps of the driving current signal and the running direction of the control rod at the step number control end of the signal simulation system.

[0162] According to an embodiment of the present invention, in step S6, the verification is repeated multiple times by changing the operating conditions of the signal simulation system and the alarm resolution in the out-of-step warning unit in the simulation measurement system. For example, the alarm resolution in the out-of-step warning unit is set to 8 steps and 1 step, and at the same time, to ensure the comparability during the verification process, the number of steps for lifting and inserting is set to 20 steps (i.e., the total number of steps).

[0163] The control rod lifting process was simulated several times for verification:

[0164] like Fig. 22As shown, the total number of steps set by the signal simulation system is set to 20, and the alarm resolution is set to 8 steps to perform the simulation operation of the lifting process. In this embodiment, after execution according to the set total number of steps, the simulation measurement system obtains the number of moving steps of the above process as 27, and the number of out-of-step steps is 7 steps, which does not reach the alarm resolution, and the out-of-step alarm is not triggered, which meets the requirements.

[0165] like Fig.23 As shown, the total number of steps set by the signal simulation system is set to 20, and the alarm resolution is set to 8 steps to perform the simulation run of the lifting process again. In this embodiment, after executing according to the set total number of steps, the simulation measurement system obtains the number of moving steps of the above process as 28, and the number of out-of-step steps is 8 steps, reaching the alarm resolution, and the out-of-step alarm is triggered, which meets the requirements.

[0166] like Fig.24 As shown, the total number of steps set by the signal simulation system is set to 20, and the alarm resolution is set to 1 step to execute the simulation run of the lifting process again. In this embodiment, after executing according to the set total number of steps, the simulation measurement system obtains the number of moving steps of the above process as 27, and the number of out-of-step steps is 7 steps, reaching the alarm resolution, and the out-of-step alarm is triggered, which meets the requirements.

[0167] The control rod insertion process was simulated several times to verify:

[0168] like Fig.25 As shown, the total number of steps set by the signal simulation system is set to -20 (i.e., the total number of steps inserted into the operation is 20), and the alarm resolution is set to 8 steps to perform the simulation operation of the lifting process. In this embodiment, after executing according to the set total number of steps, the simulation measurement system obtains the actual number of moving steps of the above process as -13, and the number of out-of-step steps is 7 steps, which does not reach the alarm resolution, and the out-of-step alarm is not triggered, which meets the requirements.

[0169] like Fig.26 As shown, the total number of steps set by the signal simulation system is set to -20 (i.e., the total number of steps inserted into the operation is 20), and the alarm resolution is set to 8 steps to perform the simulation operation of the lifting process. In this embodiment, after executing according to the set total number of steps, the simulation measurement system obtains the actual number of moving steps of the above process as -12, and the number of out-of-step steps is 8 steps, reaching the alarm resolution, and the out-of-step alarm is triggered, which meets the requirements.

[0170] like Fig. 27As shown, the total number of steps set by the signal simulation system is set to -20 (i.e., the total number of steps inserted into the operation is 20), and the alarm resolution is set to 1 step to perform the simulation operation of the lifting process. In this embodiment, after executing according to the set total number of steps, the simulation measurement system obtains the actual number of moving steps of the above process as -14, and the number of out-of-step steps is 6 steps, reaching the alarm resolution, and the out-of-step alarm is triggered, which meets the requirements.

[0171] From the above, it can be seen that the measurement method of the present invention can effectively improve the detection accuracy of the control rod travel steps by using the simulated measurement system and taking the coil driving current signal as the detection object. Compared with the detection accuracy of 8 steps of the traditional measurement system, the measurement resolution of this scheme can be improved to 1 step, which greatly improves the detection accuracy and efficiency.

[0172] According to one embodiment of the present invention, the present invention provides a measurement system constructed based on the aforementioned pressurized water reactor critical rod position measurement method, including: a signal simulation system and a simulation measurement system. In this embodiment, the signal simulation system is used to simulate and output the driving current signal of the control rod in the pressurized water reactor control rod drive system; wherein the signal simulation system includes: a normal signal simulation model, a random simulation model of the out-of-step signal, and a noise simulation model. In this embodiment, the simulation measurement system is used to simulate and measure the number of travel steps of the control rod in the pressurized water reactor control rod drive system; wherein the simulation measurement system includes: a measurement amplifier module for signal amplification, a filter module for filtering the signal, an analog / digital converter module for analog-to-digital conversion of the signal, a data preprocessing module for sampling and preprocessing the signal, and a signal restoration module for performing travel step statistics, out-of-step step statistics, and out-of-step alarm.

[0173] Through the above settings, the measurement system of the present invention can set the signal simulation system based on the actual operation data of the pressurized water reactor, so that the signal simulation system can more accurately simulate the corresponding driving current signal, and thereby debug and verify the simulation measurement system, which greatly improves the debugging efficiency, maintainability and applicability of the present invention. At the same time, the verified simulation measurement system has a high detection resolution and a fast detection speed, and can be directly used for the detection of the number of control rod travels in an actual pressurized water reactor, which greatly improves the detection accuracy of the number of control rod travels.

[0174] The above contents are merely examples of specific solutions of the present invention. For devices and structures not described in detail therein, it should be understood that they can be implemented by adopting general devices and general methods available in the art.

[0175] The above is only one solution of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for measuring the critical rod position of a pressurized water reactor, comprising: S1. Obtaining a system solution for a pressurized water reactor control rod drive system, and determining a normal operation mechanism and a step-out mechanism for a control rod lifting process in the pressurized water reactor control rod drive system based on the system solution; S2. construct a signal simulation system for simulating the output of the drive current signal of the control rod; wherein the signal simulation system comprises: a normal signal simulation model constructed based on the normal operation mechanism, a random simulation model of the out-of-step signal constructed based on the out-of-step mechanism, and a noise simulation model; S3. Constructing a simulation measurement system for simulating and measuring the number of control rod travel steps in the PWR control rod drive system; S4. Acquire historical experience data of the PWR control rod drive system during historical operation, and configure the operation rules of the normal signal simulation model and the out-of-step signal random simulation model in the signal simulation system based on the historical experience data; S5. Setting the operating conditions of the signal simulation system, the signal simulation system generates a driving current signal of the control rod based on the operating conditions and the operating rules, and the simulation measurement system performs simulation operation based on the driving current signal and outputs a detection result; S6. Repeat step S5 and verify the multiple groups of test results obtained. If the multiple groups of test results meet the requirements, connect the simulation measurement system to the actual pressurized water reactor control rod drive system for online measurement.

2. The method for measuring the critical rod position of a pressurized water reactor according to claim 1, characterized in that: In step S1, the system solution includes: a structural solution of the pressurized water reactor control rod drive system and a lifting and lowering stepping solution of the pressurized water reactor control rod drive system; wherein the structural solution includes: a drive structure for the control rod and a drive circuit for controlling the operation of the drive structure; The driving structure comprises: a moving fixture and a fixed fixture arranged along the axial direction of the control rod, a moving fixture coil corresponding to the moving fixture, a fixed fixture coil corresponding to the fixed fixture, and a lifting coil; Along the axial direction of the control rod and from top to bottom, the lifting coil, the moving fixture coil and the fixed fixture coil are arranged in sequence; The driving circuit is connected to the lifting coil, the moving fixture coil and the fixed fixture coil respectively, and is used to output driving current signals to the lifting coil, the moving fixture coil and the fixed fixture coil respectively; The lifting and lowering stepping scheme includes: a lifting action scheme and an insertion action scheme; wherein the lifting action scheme includes the operation sequence of the lifting coil, the moving clamp coil and the fixed clamp coil when lifting the control rod; and the insertion action scheme includes the operation sequence of the lifting coil, the moving clamp coil and the fixed clamp coil when inserting the control rod.

3. The method for measuring the critical rod position of a pressurized water reactor according to claim 2, characterized in that: In step S1, the step of determining the normal operation mechanism and the step-out mechanism for the control rod lifting process in the pressurized water reactor control rod drive system based on the system solution includes: Based on the structural scheme and the lifting and lowering stepping scheme, a signal timing of driving current signals of the lifting coil, the moving fixture coil and the fixed fixture coil in the control rod lifting and lowering control is obtained; Determine, based on the signal timing, a change process of the driving current signal of the movable fixture coil and the fixed fixture coil under normal operating conditions as the normal operating mechanism; Acquire signal characteristics related to the actions performed by the hooks of the mobile fixture and / or the fixed fixture during the change process; An out-of-step signal generation rule for adjusting the position of the signal feature during the change process is constructed based on the normal operation mechanism to obtain the out-of-step mechanism.

4. The method for measuring the critical rod position of a pressurized water reactor according to claim 3, characterized in that: In step S2, the normal signal simulation model includes: a first current signal model when the hook claw is not in motion, a second current signal model when the hook claw is in motion, and a third current signal model when the hook claw completes the motion; In step S2, the step of constructing a signal simulation system for outputting a driving current signal of the control rod includes: An equivalent circuit model of the driving circuit is constructed, and based on the equivalent circuit model, a first simulation formula for a driving current signal when the hook is not in motion and when the hook has completed motion is obtained, which is expressed as: A second simulation formula for the driving current signal during the hook action is constructed based on the Gaussian function, which is expressed as: Among them, a represents the amplitude, μ represents the offset, and σ represents the steepness; Constructing the first current signal model and the third current signal model on a LabVIEW simulation platform based on the first simulation formula, and constructing the second current signal model on a LabVIEW simulation platform based on the second simulation formula, and connecting the first current signal model, the third current signal model, and the second current signal model to form the normal signal simulation model; Based on the out-of-step mechanism, a random simulation model of an out-of-step signal is constructed on a LabVIEW simulation platform, and an output end of the random simulation model of the out-of-step signal is connected to an input end of the normal signal simulation model; A noise simulation model is constructed based on the LabVIEW simulation platform, and the output end of the normal signal simulation model is connected to the input end of the noise simulation model.

5. The method for measuring the critical rod position of a pressurized water reactor according to claim 3 or 4, characterized in that: In step S3, the simulation measurement system includes: a measurement amplifier module for signal amplification, a filter module for filtering the signal, an analog / digital converter module for analog-to-digital conversion of the signal, a data preprocessing module for sampling and preprocessing the signal, and a signal restoration module for performing forward step statistics, out-of-step step statistics and out-of-step alarm.

6. The method for measuring the critical rod position of a pressurized water reactor according to claim 5, characterized in that: In step S3, in the step of constructing a simulation measurement system for simulating and measuring the number of control rod travel steps in the pressurized water reactor control rod drive system, the simulation measurement system is constructed using a LabVIEW simulation platform.

7. The method for measuring the critical rod position of a pressurized water reactor according to claim 6, characterized in that: The data preprocessing module includes: a decompression module for smoothing the signal, a convolution module for removing singular items in the signal, a scale transformation module for scaling the signal, and a data output module.

8. The method for measuring the critical rod position of a pressurized water reactor according to claim 7, characterized in that: The signal restoration module includes: a step number calculation module and an information output module; The step number calculation module includes: a calculation control for calculating the number of steps of an input signal; The information output module includes: an actual moving step count unit, a lost step count unit and a lost step warning unit; The out-of-step warning unit is provided with a setting port for adjusting the alarm resolution.

9. The method for measuring the critical rod position of a pressurized water reactor according to claim 8, characterized in that: The calculation control calculates the number of steps of the input signal based on the following steps, including: Get all the peaks and troughs in the input signal; Obtaining the mean of all the peaks, and obtaining the mean of all the troughs; removing peaks smaller than the mean value among all the peaks, and removing troughs larger than the mean value among all the troughs; Merging the adjacent peaks and troughs to generate a peak-trough cycle merged signal; The number of peaks in the combined signal is counted to obtain the number of steps traveled.

10. A measurement system constructed based on the pressurized water reactor critical rod position measurement method according to any one of claims 1 to 9, characterized in that: include: Signal simulation system and simulation measurement system; The signal simulation system is used to simulate and output the driving current signal of the control rod in the control rod driving system of the pressurized water reactor; wherein the signal simulation system includes: a normal signal simulation model, a random simulation model of the out-of-step signal and a noise simulation model; The simulation measurement system is used to simulate and measure the number of travel steps of the control rods in the pressurized water reactor control rod drive system; wherein, the simulation measurement system includes: a measurement amplifier module for signal amplification, a filter module for filtering the signal, an analog / digital converter module for analog-to-digital conversion of the signal, a data preprocessing module for sampling and preprocessing the signal, and a signal restoration module for performing travel step statistics, out-of-step step statistics and out-of-step alarm.

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