Pressurized water reactor core power reconstruction method based on self-powered neutron detector

Abstract

The invention belongs to the technical field of pressurized water reactor core physical calculation, and discloses a pressurized water reactor core power reconstruction method based on a self-powered neutron detector, a nuclear power plant obtains reactor core working condition information and actual measurement data of SPND through measurement of a pressurized water reactor core nuclear measurement system, different components of a pressurized water reactor are subjected to analog calculation, and the reactor core power reconstruction method based on the self-powered neutron detector is obtained. The method comprises the steps of obtaining multi-group neutron-flux densities at SPND positions of different assemblies and different working conditions, modeling SPND, calculating SPND neutron sensitivity under different multi-group neutron-flux densities, simulating and calculating the power operation history of a pressurized water reactor to obtain reactor core theoretical data corresponding to SPND actual measurement data, and calculating the power operation history of the pressurized water reactor according to the actual measurement data of the SPND and the reactor core theoretical data. And reconstructing by adopting a proportional function fitting method to obtain three-dimensional power distribution of the reactor core. The new SPND-based power reconstruction method is provided for the pressurized water reactor using the SPND to measure the reactor core, is suitable for different types of SPNDs and can be used for various types of pressurized water reactors using the SPND to measure the reactor core, and the applicability of the SPND-based power reconstruction method is improved.

Description

Technical Field

[0001] This application belongs to the field of pressurized water reactor core physics calculation technology, and in particular relates to a pressurized water reactor core power reconfiguration method based on a self-powered neutron detector. Background Technology

[0002] Self-powered neutron detectors (SPNDs) operate within a pressurized water reactor for extended periods, exhibiting characteristics of solid-state detectors and capable of outputting measurement data in real time. SPNDs can be categorized into two types: decay-type and transient-type. For decay-type SPNDs (with rhodium, vanadium, or silver emitters), the current primarily originates from β and γ decay reactions caused by neutrons captured at the emitter, as well as a small amount of external γ-ray reactions. In contrast, transient-type SPNDs (with cobalt, platinum, or chromium emitters) primarily derive their current from γ decay reactions caused by neutrons captured at the emitter and external γ-ray reactions.

[0003] Due to the limited number of detector channels in the core nuclear measurement system of pressurized water reactors (PWRs), it is necessary to obtain the three-dimensional power distribution of the core through power reconstruction during PWR operation. This is used to calculate key physical parameters such as axial offset, hot spot heat pipe factor, and quadrant tilt power factor, ensuring core safety during operation. Currently, in domestic commercial PWRs, VVER uses a rhodium SPND to measure the core and employs an upper-level computer system to reconstruct the core power; AP1000 uses the BEACON system combined with measurements and calculations from a vanadium SPND to reconstruct the core power; and EPR uses the AMS system and a cobalt SPND system in conjunction to reconstruct the core power. These power reconstruction methods are all from abroad and differ from one another. Many aspects of their data processing methods and power reconstruction principles remain unclear and require further research. Summary of the Invention

[0004] The purpose of this application is to overcome the shortcomings of the prior art and provide a method for power reconfiguration of pressurized water reactor core based on a self-powered neutron detector.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] A method for power reconfiguration of pressurized water reactor core based on a self-powered neutron detector includes:

[0007] Step 1: The nuclear power plant obtains core operating condition information and SPND measured data through the pressurized water reactor core nuclear testing system;

[0008] Step 2: Use core physics calculation software to simulate and calculate different components of the pressurized water reactor to obtain the multi-group neutron flux density at SPND of different components under different operating conditions;

[0009] Step 3: Model the SPND using the Monte Carlo program and calculate the SPND neutron sensitivity under different multi-group neutron flux densities;

[0010] Step 4: Use core physics calculation software to simulate and calculate the power operation history of the pressurized water reactor to obtain the core theoretical data corresponding to the SPND measured data;

[0011] Step 5: Combining the measured data from SPND and the theoretical data from the reactor core, the three-dimensional power distribution of the reactor core is reconstructed using the proportional function fitting method.

[0012] In some embodiments, core operating information includes core burnup, power level, boric acid concentration, control rod position, thermocouple temperature, and external detector readings.

[0013] In some embodiments, the operating history of the pressurized water reactor core is simulated and calculated based on the core operating condition information to obtain the corresponding theoretical core data.

[0014] In some embodiments, the measured data of the SPND includes the original measured current of the SPND. The accumulated charge Y of the SPND is used to correct for the losses of the SPND emitter during long-term use, resulting in the measured SPND current I used for power reconfiguration. m .

[0015] In some embodiments, the accumulated charge Y of the SPND and the measured current I of the SPND are... m The calculation formula is as follows:

[0016]

[0017] In the formula, t is the SPND working time; I m is the measured current of SPND; B is the SPND fuel consumption correction function.

[0018] In some embodiments, core physics calculation software is used to model different components of the pressurized water reactor. The restart function of the core physics calculation software is used to calculate the neutron flux density distribution of the components under different operating conditions, and the multi-group neutron flux density at the SPND placement location within the component is obtained.

[0019] In some embodiments, the SPND is modeled using a Monte Carlo procedure, with the magnitude and energy of the multi-group neutron flux density set as the neutron source input, and the current I generated at the collecting electrode is statistically analyzed. n Based on the single-group neutron flux density The corresponding SPND neutron sensitivity S was obtained. n .

[0020] In some embodiments, single-group neutron flux density SPND Neutron Sensitivity S n The calculation formula is as follows:

[0021]

[0022] In the formula, I is the neutron flux density of the g-th group; G is the total energy group number of the neutron flux density; n The current generated at the collector of SPND;

[0023] In some embodiments, the SPND neutron sensitivity of different components under different operating conditions is calculated using a Monte Carlo program. The discrete SPND neutron sensitivity is fitted to obtain a continuous SPND neutron sensitivity function. The three-dimensional SPND neutron sensitivity is calculated based on the core operating condition information. Then, combined with the single-group neutron flux density at the SPND, the SPND calculated current I is obtained. c The calculation formula is as follows:

[0024] S n (Tf,Tm,BC,Bu)=S n,b (Tf b ,Tm b ,BC b ,Bu)+dS n (Tf,Tm,BC,Bu);

[0025]

[0026] In the formula, S n,b The neutron sensitivity of the reactor core under reference operating conditions at any burnup point; dS n Tf represents the change in neutron sensitivity due to differences between operating parameters and baseline operating parameters at any burnup point; Tf, Tm, BC, and Bu represent fuel temperature, moderator temperature, boric acid concentration, and burnup, respectively; Tf b ,Tm b ,BC b The parameters are: fuel temperature, moderator temperature, and boric acid concentration under reference operating conditions; I c Calculate the current for SPND; r s This refers to the location of SPND.

[0027] In some embodiments, the scaling function is defined as the ratio of the measured value of the SPND current to the calculated value of the SPND current. Then, the scaling function h at SPND... s for:

[0028]

[0029] By fitting the proportional function at SPND layer by layer using polynomial axial fitting, and solving for the polynomial coefficients, the proportional function h of the entire core is obtained as follows:

[0030]

[0031] minσ 2 =∑(h(r) s )-h s (r s )) 2

[0032] In the formula, r represents the position of the core assembly; x, y, z represent the three-dimensional positions of the core assembly; L represents the highest order of the polynomial; u, v represent the orders of the polynomials; h represents the scaling function of the entire core; a uv σ represents the polynomial coefficients for orders u and v; min is the minimum value; σ 2 This is the sum of squared residuals between the scaling function of the entire core and the scaling function at SPND;

[0033] Based on the fundamental assumptions of the proportional function fitting method, the calculated core power value is corrected by the proportional function of the entire core, and the reconstructed core power value is obtained, thus completing the power reconstruction of the entire pressurized water reactor core, as shown in the following formula:

[0034] P r (r)=P c (r)h(r);

[0035] In the formula, P r P represents the core power reconfiguration value. c This is the calculated value for the reactor core power.

[0036] Compared with existing technologies, the pressurized water reactor core power reconfiguration method based on a self-powered neutron detector provided in this application has the following advantages:

[0037] This application uses the Monte Carlo program to calculate the neutron sensitivity of the SPND, then uses core physics calculation software to obtain the core theoretical data, and finally uses the proportional function fitting method to perform power reconstruction to obtain the three-dimensional power distribution of the core. This provides a new SPND-based power reconstruction method for pressurized water reactors that use SPND to measure the core, filling a technological gap.

[0038] The types of SPNDs used in nuclear power plant units such as VVER, EPR, and AP100 are different, and the corresponding SPND-based power reconfiguration methods are also different. This method can be applied to different types of SPNDs and can be used for all types of pressurized water reactors that use SPNDs to measure the reactor core, thus increasing the applicability of the SPND-based power reconfiguration method.

[0039] The Monte Carlo program takes too long to calculate the neutron sensitivity of the SPND, making it difficult to meet the real-time characteristics of the SPND. Therefore, this application uses the Monte Carlo program to create an SPND neutron sensitivity library in advance, so that the Monte Carlo program is no longer used for calculation during power reconfiguration, shortening the power reconfiguration time based on the SPND and making it meet the requirements of real-time online monitoring of pressurized water reactors based on the SPND. Attached Figure Description

[0040] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the technical description will be briefly introduced below.

[0041] Figure 1 A flowchart of the pressurized water reactor core power reconfiguration method based on a self-powered neutron detector provided in this application;

[0042] Figure 2 The structure diagram of the SPND provided in this application;

[0043] Figure 3 A schematic diagram showing the measured current, calculated current, and relative error between the measured and calculated current of the first layer SPND in the VVER axial direction provided in this application;

[0044] Figure 4 A schematic diagram showing the measured current, calculated current, and relative error between the measured and calculated current of the second layer SPND in the VVER axial direction provided in this application;

[0045] Figure 5 A schematic diagram showing the measured current, calculated current, and relative error between the measured and calculated current of the third layer SPND in the VVER axial direction provided in this application;

[0046] Figure 6 A schematic diagram showing the measured current, calculated current, and relative error between the measured and calculated current of the 4th layer SPND in the VVER axial direction provided in this application;

[0047] Figure 7 A schematic diagram showing the measured current, calculated current, and relative error between the measured and calculated current of the 5th layer SPND in the VVER axial direction provided in this application;

[0048] Figure 8 A schematic diagram showing the measured current, calculated current, and relative error between the measured and calculated current of the 6th layer SPND in the VVER axial direction provided in this application;

[0049] Figure 9 A schematic diagram showing the measured current, calculated current, and relative error between the measured and calculated current of the 7th layer SPND in the VVER axial direction provided in this application;

[0050] Figure 10The diagram provided in this application shows the reconstructed value, calculated value, and absolute error between the reconstructed power and the calculated power for the radial power distribution of the VVER core.

[0051] Figure 11 This is a schematic diagram showing the reconstructed value, calculated value, and absolute error between the reconstructed power and the calculated power for the VVER core axial power distribution provided in this application.

[0052] Explanation of reference numerals in the attached figures

[0053] 1. Emitter; 2. Insulating layer; 3. Collector; 4. Communication line; 5. Communication line sheath; 6. Communication line insulation layer; 7. Signal core; 8. Background core; 9. Sealed terminal; 10. Current terminal. Detailed Implementation

[0054] The following detailed description provides further details on specific implementation methods.

[0055] like Figure 1 As shown, this application provides a method for power reconfiguration of a pressurized water reactor core based on a self-powered neutron detector, comprising:

[0056] Step 1: The nuclear power plant obtains core operating condition information and measured data from the self-sufficient neutron detector (SPND) through the pressurized water reactor core nuclear measurement system;

[0057] Step 2: Use core physics calculation software to simulate and calculate different components of the pressurized water reactor to obtain the multi-group neutron flux density at SPND of different components under different operating conditions;

[0058] Step 3: Model the SPND using the Monte Carlo program and calculate the SPND neutron sensitivity under different multi-group neutron flux densities;

[0059] Step 4: Use core physics calculation software to simulate and calculate the power operation history of the pressurized water reactor to obtain the core theoretical data corresponding to the SPND measured data;

[0060] Step 5: Combining the measured data from SPND and the theoretical data from the reactor core, the three-dimensional power distribution of the reactor core is reconstructed using the proportional function fitting method.

[0061] In step 1, the core operating information measured by the pressurized water reactor core verification system includes core burnup, power level, boric acid concentration, control rod position, thermocouple temperature, and external detector readings. When using core physics calculation software in the subsequent process, the core operating information is used to accurately simulate and calculate the power operation history of the pressurized water reactor core, and obtain the corresponding core theoretical data.

[0062] The radial distribution of SPNDs within the pressurized water reactor (PWR) is limited, while the axial number varies depending on the specific PWR. Furthermore, due to their long-term location within the PWR, real-time measured data can be output. This measured data includes the raw measured current of the SPNDs, denoted as […]. The accumulated charge of the SPND is denoted as Y. The accumulated charge of the SPND is used to correct for the losses of the SPND emitter during long-term use, and the measured current of the SPND used for power reconfiguration is denoted as I. m As shown in formulas (1) and (2):

[0063]

[0064] In the formula:

[0065] —Original SPND measured current;

[0066] Y—Accumulated charge of SPND;

[0067] t — SPND working time;

[0068] I m —Measured current of SPND;

[0069] B—SPND fuel consumption correction function.

[0070] In one embodiment, the core measured data file of the first cycle of a domestic pressurized water reactor unit is used, which includes core operating information such as equivalent full power day (burnup) of 58.389 MWd, boric acid concentration of 4.72 g / kg, and power level of 2978.8 MW, as well as the original measured current and accumulated charge of SPND of 54 radial and 7 axial points in the core.

[0071] In step 2, core physics calculation software is used to model different components of the pressurized water reactor. The restart function of the core physics calculation software is used to calculate the neutron flux density distribution of the components under different operating conditions (burnup, boric acid concentration, fuel temperature, moderator temperature and control rods), and the multi-group neutron flux density at the SPND placed in the component is obtained. These multi-group neutron flux densities at the SPND of different components under different operating conditions are used for subsequent Monte Carlo program calculation of the neutron sensitivity of the SPND.

[0072] In one embodiment, the LOCUST component calculation program under Bamboo-C, a domestically developed core physics calculation software, is used to model different components of the pressurized water reactor. The SPND is placed in the component instrumentation tube. Using the LOCUST restart function, the 69 group neutron flux density at the component SPND under different operating conditions is obtained.

[0073] In step 3, the SPND consists of three parts from the inside out: an emitter, an insulating layer, and a collector. When the SPND is working, neutrons strike the emitter and react to produce electrons. These electrons then pass through the insulating layer to reach the collector, thus generating a current. The SPND is modeled using a Monte Carlo program, with the magnitude and energy of the multi-group neutron flux density set as the neutron source input. The current generated at the collector is statistically recorded as I. n Based on the single-group neutron flux density, it is denoted as The corresponding SPND neutron sensitivity is denoted as S. n For example, formulas (3) and (4):

[0074]

[0075] In the formula:

[0076] —Single-group neutron flux density;

[0077] — Neutron flux density of the g-th group;

[0078] G—Neutron flux density—Total energy group number;

[0079] I n —The current generated at the collector of SPND;

[0080] S n —SPND neutron sensitivity.

[0081] In one embodiment, the GEANT4 Monte Carlo program is used to simulate the physical process of neutrons striking the SPND. The rhodium SPND of the pressurized water reactor is modeled using GEANT4, such as... Figure 2 The structure diagram of the SPND is shown. Different 69-group neutron flux densities are used as neutron sources, and the corresponding SPND neutron sensitivities are calculated. For example... Figure 2 As shown, the structure of the SPND includes an emitter 1, an insulating layer 2, a collector 3, a communication line 4, a communication line sheath 5, a communication line insulating layer 6, a signal core 7, a background core 8, a sealing terminal 9, and a current terminal 10.

[0082] In step 4, the core physics calculation software is used to simulate and calculate the power operation history of the pressurized water reactor. Based on the core operating condition information corresponding to the SPND measured data, the corresponding core theoretical data are calculated, including the calculated values ​​of three-dimensional burnup distribution, three-dimensional power distribution, single-group neutron flux density distribution at the three-dimensional SPND, hot spot factor, heat pipe factor, etc.

[0083] The SPND neutron sensitivity of different components under different operating conditions was calculated using the Monte Carlo program. The discrete SPND neutron sensitivity was fitted to obtain the continuous SPND neutron sensitivity function, as shown in formula (5). Then, the core physics calculation software can calculate the three-dimensional SPND neutron sensitivity based on the core operating condition information. Combined with the single-group neutron flux density at the SPND, the SPND calculation current is obtained, denoted as I. c As shown in formula (6):

[0084] S n (Tf,Tm,BC,Bu)=S n,b (Tf b ,Tm b ,BC b ,Bu)+dS n Formula (5) (Tf,Tm,BC,Bu)

[0085]

[0086] In the formula:

[0087] S n,b — Neutron sensitivity of the reactor core under reference operating conditions at any burnup point;

[0088] dS n —The change in neutron sensitivity due to the difference between the operating parameters and the reference operating parameters at any burn-out point;

[0089] Tf, Tm, BC, Bu — fuel temperature, moderator temperature, boric acid concentration, fuel consumption;

[0090] Tf b ,Tm b ,BC b —The fuel temperature, moderator temperature, and boric acid concentration under the reference operating conditions are generally constant values;

[0091] I c SPND calculates the current;

[0092] r s —The location of SPND.

[0093] In one embodiment, the SPARK core calculation program under the Bamboo-C core physics calculation software simulates the power operation history of a domestic pressurized water reactor unit during its first cycle. Based on the core operating condition information in the measured core data file, SPARK calculates and outputs the corresponding theoretical core data file THE-BU. Simultaneously, using the LTOS component minority group homogenization constant parameterization program under Bamboo-C, the SPND neutron sensitivity of different components under different operating conditions calculated by GEANT4 is fitted into a continuous function and provided to SPARK. SPARK can then calculate the SPND calculation current based on the theoretical core operating condition information, such as... Figures 3 to 9 As shown, the measured current, calculated current, and relative error between the measured and calculated currents of the SPND layers 1 to 7 along the axial direction of a pressurized water reactor in China are presented.

[0094] In step 5, the basic assumption of the proportional function fitting method is that the ratio of the reconstructed core power value to the calculated power value is equal to the ratio of the measured SPND current value to the calculated SPND current value. The proportional function is defined as the ratio of the measured SPND current value to the calculated SPND current value, so the proportional function at SPND is denoted as h. s As in formula (7):

[0095]

[0096] In the formula:

[0097] h s —The scaling function at SPND.

[0098] The scaling function at SPND has values ​​only on some core components. By fitting polynomials axially layer by layer, the scaling function at SPND is fitted to all core components. During the fitting process, the sum of squared residuals between the scaling function of the entire core and the scaling function at SPND is minimized to solve for the polynomial coefficients, and thus the scaling function of the entire core is obtained, denoted as h, as shown in formulas (8) and (9):

[0099]

[0100] minσ 2 =∑(h(r) s )-h s (r s )) 2 Formula (9)

[0101] In the formula:

[0102] r—position of the core assembly;

[0103] x, y, z — Three-dimensional position of the core assembly;

[0104] L—the highest order of the polynomial, usually taken as order 2;

[0105] u, v — the order of the polynomial;

[0106] h—the scaling function of the entire core;

[0107] a uv —Polynomial coefficients for orders u and v;

[0108] min — minimum value;

[0109] σ 2 —The sum of squared residuals between the scaling function of the entire core and the scaling function at SPND.

[0110] Finally, based on the fundamental assumptions of the proportional function fitting method, the calculated core power value is corrected by the proportional function of the entire core, and the reconstructed core power value is obtained, thus completing the power reconstruction of the entire pressurized water reactor core, as shown in formula (10):

[0111] P r (r)=P c Formula (10) (r)h(r)

[0112] In the formula:

[0113] P r —Core power reconfiguration value;

[0114] P c —Calculated core power.

[0115] In one embodiment, the pressurized water reactor core power reconfiguration software 3DPOWER under the core physics calculation software Bamboo-C is used to read the core measured data file and the core theoretical data file THE-BU to perform power reconfiguration and obtain the three-dimensional power distribution reconfiguration value of a certain pressurized water reactor core in China.

[0116] Figure 10 The reconstructed value, calculated value, and absolute error between the reconstructed power and the calculated power are given for the radial power distribution of a certain pressurized water reactor core in China. The absolute error range for radial power is [-0.05, 0.04]. Figure 11 The reconstructed value, calculated value, and absolute error between the reconstructed power and the calculated power are the axial power distribution of a certain pressurized water reactor core in China. The absolute error range of axial power is [-0.07, 0.04]. Both radial power and axial power meet the operating limits of a certain pressurized water reactor in China, which require that the absolute error of power greater than 1 should be less than 0.1 and the absolute error of power less than 1 should be less than 0.25.

[0117] Therefore, the pressurized water reactor core power reconfiguration method based on a self-powered neutron detector provided in this application can accurately calculate the power distribution of the pressurized water reactor core.

[0118] The above description is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application.

Claims

1. A method for power reconfiguration of pressurized water reactor core based on a self-sufficient neutron detector, characterized in that, include: Step 1: The nuclear power plant obtains core operating condition information and SPND measured data through the pressurized water reactor core nuclear testing system; Step 2: Use core physics calculation software to simulate and calculate different components of the pressurized water reactor to obtain the multi-group neutron flux density at SPND of different components under different operating conditions; Step 3: Model the SPND using the Monte Carlo program and calculate the SPND neutron sensitivity under different multi-group neutron flux densities; Step 4: Use core physics calculation software to simulate and calculate the power operation history of the pressurized water reactor to obtain the core theoretical data corresponding to the SPND measured data; Step 5: Combining the measured data from SPND and the theoretical data from the reactor core, the three-dimensional power distribution of the reactor core is reconstructed using the proportional function fitting method.

2. The pressurized water reactor core power reconfiguration method based on a self-powered neutron detector according to claim 1, characterized in that, In step 1, the core operating information includes core burnup, power level, boric acid concentration, control rod position, thermocouple temperature, and external detector readings.

3. The pressurized water reactor core power reconfiguration method based on a self-powered neutron detector according to claim 2, characterized in that, Based on the core operating condition information, the operating history of the pressurized water reactor core is simulated and calculated to obtain the corresponding theoretical core data.

4. The pressurized water reactor core power reconfiguration method based on a self-powered neutron detector according to claim 1, characterized in that, In step 1, the measured data includes the original measured current of the SPND. The accumulated charge Y of the SPND is used to correct for the losses of the SPND emitter during long-term use, resulting in the measured SPND current I used for power reconfiguration. m .

5. The pressurized water reactor core power reconfiguration method based on a self-powered neutron detector according to claim 4, characterized in that, The accumulated charge Y of SPND and the measured current I of SPND m The calculation formula is as follows: In the formula, t is the SPND working time; I m is the measured current of SPND; B is the SPND fuel consumption correction function.

6. The pressurized water reactor core power reconfiguration method based on a self-powered neutron detector according to claim 1, characterized in that, In step 2, core physics calculation software is used to model different components of the pressurized water reactor. The restart function of the core physics calculation software is used to calculate the neutron flux density distribution of the components under different operating conditions, and the multi-group neutron flux density at the SPND location within the component is obtained.

7. The pressurized water reactor core power reconfiguration method based on a self-powered neutron detector according to claim 1, characterized in that, In step 3, the SPND is modeled using a Monte Carlo program, with the magnitude and energy of the multi-group neutron flux density set as the input of the neutron source, and the current I generated at the collecting electrode is statistically analyzed. n Based on single-group neutron flux density The corresponding SPND neutron sensitivity S was obtained. n .

8. The pressurized water reactor core power reconfiguration method based on a self-powered neutron detector according to claim 7, characterized in that, Single-group neutron flux density SPND Neutron Sensitivity S n The calculation formula is as follows: In the formula, I is the neutron flux density of the g-th group; G is the total energy group number of the neutron flux density; n The current generated at the collector of SPND.

9. The pressurized water reactor core power reconfiguration method based on a self-powered neutron detector according to claim 1, characterized in that, In step 4, the SPND neutron sensitivity of different components under different operating conditions is calculated using a Monte Carlo program. The discrete SPND neutron sensitivity is fitted to obtain a continuous SPND neutron sensitivity function. The three-dimensional SPND neutron sensitivity is calculated based on the core operating condition information. Then, combined with the single-group neutron flux density at the SPND, the SPND calculated current I is obtained. c The calculation formula is as follows: S n (Tf,Tm,BC,Bu)=S n,b (Tf b ,Tm b BC b ,Bu)+dS n (Tf,Tm,BC,Bu) In the formula, S n,b The neutron sensitivity of the reactor core under reference operating conditions at any burnup point; dS n Tf represents the change in neutron sensitivity due to differences between operating parameters and baseline operating parameters at any burnout point; Tm, BC, and Bu represent fuel temperature, moderator temperature, boric acid concentration, and burnout, respectively; Tf b Tm b BC b The parameters are: fuel temperature, moderator temperature, and boric acid concentration under reference operating conditions; I c Calculate the current for SPND; r s This refers to the location of SPND.

10. The pressurized water reactor core power reconfiguration method based on a self-powered neutron detector according to claim 1, characterized in that, In step 5, the proportional function is defined as the ratio of the measured value of the SPND current to the calculated value of the SPND current. Therefore, the proportional function h at SPND is... s for: By fitting the proportional function at SPND layer by layer using polynomial axial fitting, and solving for the polynomial coefficients, the proportional function h of the entire core is obtained as follows: minσ 2 =∑(h(r s )-h s (r s )) 2 In the formula, r represents the position of the core assembly; x, y, z represent the three-dimensional positions of the core assembly; L represents the highest order of the polynomial; u, v represent the orders of the polynomials; h represents the scaling function of the entire core; a uv For polynomials of order u and v; min is the minimum value; σ 2 This is the sum of squared residuals between the scaling function of the entire core and the scaling function at SPND; Based on the fundamental assumptions of the proportional function fitting method, the calculated core power value is corrected by the proportional function of the entire core, and the reconstructed core power value is obtained, thus completing the power reconstruction of the entire pressurized water reactor core, as shown in the following formula: P r (r)=P c (r)h(r); In the formula, P r P represents the core power reconfiguration value. c This is the calculated value for the reactor core power.

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