Reactor neutron detector calibration method and system and computer equipment

Abstract

The invention discloses a reactor neutron detector calibration method, a reactor neutron detector calibration system and computer equipment, and relates to the technical field of nuclear reactor core monitoring. The absolute neutron flux at the position of the out-of-pile neutron detector is mapped, the corresponding relation between the measurement result of the neutron detector and the absolute neutron flux at the position of the neutron detector is obtained, and the absolute neutron flux at the position of the detector can be rapidly and accurately obtained based on the corresponding relation and the measurement result of the neutron detector. According to the method, the conversion factor of the neutron detector is calibrated at one time only by using an activation method, and the absolute neutron flux at the detector can be directly obtained through the measurement result of the neutron detector under various conditions of change of reactor core arrangement, change of the rod state of a reactor core control rod, change of reactor core power and the like subsequently; multiple irradiation experiments are not needed, so that the measurement efficiency is improved, and the cost is saved.

Description

Technical Field

[0001] The present application relates to the technical field of nuclear reactor core monitoring, and in particular to a reactor neutron detector calibration method, system and computer equipment. Background Art

[0002] After the production and manufacturing of neutron detectors at home and abroad is completed, only the value range of the detector sensitivity will be given, and the conversion factor corresponding to the detector measurement result and the neutron flux will not be accurately given. That is, the absolute neutron flux at the detector cannot be determined by the measurement result of the detector. At this time, based on the measurement result of the detector, only the changing trend of the core state can be judged, but it is impossible to determine the absolute neutron flux of the core, the absolute power of the core, and other important physical parameters that can characterize the actual operation state of the reactor.

[0003] The traditional method is to use the activation method to arrange activation plates in the reactor, and after irradiating the core for a certain period of time, measure the activity after irradiation and then inversely calculate the core absolute neutron flux or absolute power and other parameters. When the traditional method is used, when the core layout state changes, it is necessary to use the activation method to open the reactor multiple times to carry out irradiation experiments to determine the core absolute neutron flux and absolute power. In addition, if the core flux level changes after the core power is increased or decreased, the absolute neutron flux and absolute power previously determined by the activation method are no longer applicable. Summary of the invention

[0004] In order to solve the problems existing in the traditional methods, the present application proposes a reactor neutron detector calibration method, system and computer equipment. The present application is based on the absolute neutron flux at a certain position of the reactor core measured by the activation method, combined with the distribution relationship of the neutron flux inside and outside the core, to map the absolute neutron flux at the position of the neutron detector outside the core, and obtain the corresponding relationship between the neutron detector measurement result and the absolute neutron flux at the neutron detector. Based on the corresponding relationship and the neutron detector measurement result, the absolute neutron flux at the detector can be quickly and accurately obtained. The present application only uses the activation method to calibrate the conversion factor of the neutron detector once. In the subsequent changes in the core layout, the state of the core control rods, the core power and other situations, the absolute neutron flux at the detector can be obtained through the measurement results of the neutron detector. Then, through the distribution relationship of the neutron flux inside and outside the core, the core absolute flux distribution and the core absolute power and other physical parameters that can characterize the actual operating state of the core can be determined, without multiple irradiation experiments, which improves the measurement efficiency and saves costs.

[0005] This application is implemented through the following technical solutions:

[0006] A reactor neutron detector calibration method, the calibration method comprising:

[0007] The proportional relationship between the normalized calculated value of the neutron flux at the activation plate position and the normalized calculated value of the neutron flux at the neutron detector position is calculated using the core physics calculation and analysis software;

[0008] The absolute value of the neutron flux at the position of the activation sheet is measured by the activation method, and the absolute value of the neutron flux at the position of the neutron detector is obtained according to the proportional relationship;

[0009] Calibrate a neutron detector conversion factor according to the neutron detector measurement result and the absolute value of the neutron flux at the position of the neutron detector;

[0010] The neutron detector conversion factor is the ratio of the neutron detector measurement result to the absolute value of the neutron flux at the position of the neutron detector.

[0011] In some embodiments, the ratio of the normalized calculated value of the neutron flux at the activation plate position and the normalized calculated value of the neutron flux at the neutron detector position calculated by the core physics calculation analysis software specifically includes:

[0012] According to the specific arrangement and material composition of the reactor core components and activation plates, neutron detectors, and reactor vessels, a theoretical calculation model is established using the core physics calculation and analysis software;

[0013] Using typical critical rod positions in the core obtained through actual reactor measurements to calibrate and verify the established theoretical calculation model;

[0014] According to the actual critical rod position state of the reactor, adjust the safety rod and other control rod positions of the theoretical calculation model after verification and validation, so that the rod position states of all control rods in the theoretical calculation model are consistent with the actual measured rod position states of the reactor;

[0015] After the rod position states are adjusted to be consistent, the initial parameters are set, and parallel calculations are performed to obtain the normalized calculated value of the neutron flux at the activation sheet position and the normalized calculated value of the neutron flux at the neutron detector position, and the calculation deviation is controlled within a preset range;

[0016] A proportional relationship between a normalized calculated value of the neutron flux at the activation plate position and a normalized calculated value of the neutron flux at the neutron detector position is obtained.

[0017] In some embodiments, the process of establishing the theoretical calculation model follows the order from inside to outside and from small to large, and accurately describes the fuel grid element, fuel assembly, core, core shroud, reflector layer, and reactor vessel, and accurately models the activation plate and neutron detector according to their actual size and spatial position.

[0018] In some embodiments, the step of measuring the absolute value of the neutron flux at the position of the activation sheet using the activation method, and obtaining the absolute value of the neutron flux at the position of the neutron detector according to the proportional relationship, specifically includes:

[0019] After the activation sheet is irradiated in the core, the absolute value of the neutron flux at the position of the activation sheet is measured using a gamma spectrometer and an absolute neutron flux measurement system;

[0020] According to the core power distribution characteristics of the reactor and the synchronous fluctuation characteristics of the core under the same state, it is obtained that the proportional relationship between the normalized calculated value of the neutron flux at the activation plate position and the normalized calculated value of the neutron flux at the neutron detector position is equal to the proportional relationship between the absolute value of the neutron flux at the activation plate position and the absolute value of the neutron flux at the neutron detector position;

[0021] According to the absolute value of the neutron flux at the position of the activation sheet and the proportional relationship, the absolute value of the neutron flux at the position of the neutron detector is obtained.

[0022] In some embodiments, for a neutron detector of a neutron counting tube type, the measurement result of the neutron detector is the number of counts.

[0023] In some embodiments, for an ionization chamber type neutron detector, the neutron detector measurement result is a current value.

[0024] In a second aspect, the present application proposes a reactor neutron detector calibration system, the calibration system comprising:

[0025] A model calculation module, wherein the model calculation module uses core physics calculation and analysis software to calculate a proportional relationship between a normalized calculated value of neutron flux at an activation plate position and a normalized calculated value of neutron flux at a neutron detector position;

[0026] A measurement and calculation module, wherein the measurement and calculation module measures the absolute value of the neutron flux at the position of the activation sheet by using an activation method, and obtains the absolute value of the neutron flux at the position of the neutron detector according to the proportional relationship;

[0027] and, a conversion module, wherein the conversion module calibrates and obtains a neutron detector conversion factor according to the neutron detector measurement result and the absolute value of the neutron flux at the position of the neutron detector;

[0028] The neutron detector conversion factor is the ratio of the neutron detector measurement result to the absolute value of the neutron flux at the position of the neutron detector.

[0029] In some embodiments, the model calculation module further includes:

[0030] A model building unit, wherein the model building unit uses the core physics calculation and analysis software to establish a theoretical calculation model according to the specific arrangement and material composition of the reactor core components and activation plates, neutron detectors, and reactor vessels;

[0031] A verification unit, wherein the verification unit uses typical critical rod positions in the core obtained through actual reactor measurements to check and verify the established theoretical calculation model;

[0032] An adjustment unit, wherein the adjustment unit adjusts the safety rods and other control rod positions of the theoretical calculation model after verification and validation according to the actual critical rod position state of the reactor, so that the rod position states of all control rods in the theoretical calculation model are consistent with the actual measured rod position states of the reactor;

[0033] And, an iterative calculation unit, which sets initial parameters and performs parallel calculations to obtain a normalized calculated value of the neutron flux at the activation plate position and a normalized calculated value of the neutron flux at the neutron detector position, thereby obtaining a proportional relationship between the normalized calculated value of the neutron flux at the activation plate position and the normalized calculated value of the neutron flux at the neutron detector position.

[0034] In a third aspect, the present application proposes a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0035] In a fourth aspect, the present application proposes a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0036] The present application proposes a reactor neutron detector calibration method, system and computer equipment, which use an activation method to calibrate the conversion factor of the neutron detector at one time. In various situations such as changes in the core layout, changes in the state of the core control rods, and changes in the core power, there is no need to restart the reactor for activation irradiation experiments. The absolute value of the neutron flux at the neutron detector can be directly obtained by combining the measurement results of the neutron detector with the conversion factor obtained by calibration. Then, the physical parameters that can characterize the actual operating state of the core, such as the core absolute flux distribution and the core absolute power, can be determined through the relationship between the neutron flux distribution inside and outside the core.

[0037] The present application proposes a reactor neutron detector calibration method, system and computer equipment. When using the calibrated neutron detector to monitor the core state or measure important physical parameters of the core, the absolute measurement values ​​of the core absolute neutron flux and absolute power, which can characterize the actual operating state of the reactor, can be intuitively obtained. It is not necessary to use the traditional activation method to open the core multiple times to measure the above parameters when the core layout or core state changes, thereby reducing the number of times the core is opened, saving time, saving manpower, reducing the radiation of personnel and avoiding the use of activation plates.

[0038] The present application proposes a reactor neutron detector calibration method, system and computer equipment, which reduces the loss of reactor and supporting system equipment and improves scientific research and production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings described herein are used to provide a further understanding of the embodiments of the present application, constitute a part of the present application, and do not constitute a limitation on the embodiments of the present application. In the drawings:

[0040] Figure 1 Schematic diagram of the gold sheet irradiation and activity change process of the embodiment of the present application; wherein (a) is a schematic diagram of the gold sheet irradiation process; (b) is a schematic diagram of the activity change process;

[0041] Figure 2 For the embodiments of this application 198 Au decay scheme;

[0042] Figure 3 A schematic diagram of a calibration method flow chart of an embodiment of the present application;

[0043] Figure 4 This is a schematic diagram of the arrangement of the core activation plates and neutron detectors of an embodiment of the present application;

[0044] Figure 5 The neutron flux distribution diagram calculated for the embodiment of the present application;

[0045] Figure 6 This is a principle block diagram of the calibration system of an embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with examples and drawings. The illustrative implementation scheme of the present application and its description are only used to explain the present application and are not intended to limit the present application.

[0047] Example:

[0048] The traditional technology of measuring the core neutron flux by activation method is to arrange activation plates in the reactor, irradiate the core for a certain period of time, measure the activity after irradiation, and then calculate the absolute neutron flux or absolute power of the core. Typical activation plates are Mn-Ni (manganese-nickel) plates and Au (gold) plates. Figure 1 Gold sheet irradiation (a) and activity change process (b).

[0049] The net growth rate of radionuclides during irradiation is:

[0050]

[0051] Where n(t) is the radionuclide 198 The number of Au nuclei; φ0 is the thermal neutron flux with an energy of 0.025 eV, 1 / (cm 2 ·s); σ0 is 197 Au thermal neutron microscopic radiation capture cross section, σ0 = 98.8b (1b = 10 -24 cm 2 ); N is 197 The number of Au nuclei, a constant; λ is 198 Decay constant of Au, s -1 , which represents the probability of an atomic nucleus decaying per unit time.

[0052] Solve equation (1) and substitute the initial conditions, that is, when t = t1 (not considering the power increase stage), the activated product 198 The number of Au nuclei n(t) = 0. We get:

[0053]

[0054] At the end of irradiation, time t2 198 The number of Au nuclei:

[0055]

[0056] After irradiation, 198 Au is no longer generated, only decay decreases, and the half-life is T 1 / 2 = 2.696 days, see the decay diagram Figure 2 .

[0057] Then, the number of activated detector nuclei at time t after the irradiation is completed is:

[0058]

[0059] The radioactivity corresponding to formula (4) is:

[0060]

[0061] like Figure 1 As shown, during the measurement time Δt from t3 to t4, the count of 0.412MeV gamma rays is:

[0062]

[0063] Solving equation (6), we can obtain:

[0064]

[0065] Where b is the background count rate, s -1 ; T L is the live time during the γ spectrometer measurement, s; T R is the real time during the γ spectrometer measurement, s; m0 is the mass of the activated film, mg; M is the relative atomic mass; N a is Avogadro's constant, 6.02×10 23 mol -1 ; ε is the absolute detection efficiency of the γ spectrometer for γ rays; P γ for 198 The gamma ray intensity during Au decay, P γ =95.5%.

[0066] make Then formula (7) can be simplified as:

[0067]

[0068] Formula (8) is the theoretical calculation formula required to measure the absolute neutron flux.

[0069] However, the above traditional methods need to re-conduct irradiation experiments to determine the absolute neutron flux and absolute power of the core when the core layout state changes, the core control rod state changes, the core power changes, etc., resulting in low measurement efficiency and high cost.

[0070] In view of this, the present embodiment proposes a method for calibrating a reactor neutron detector. The method proposed in the present application uses an activation method to calibrate the conversion factor of the neutron detector at one time, and then directly obtains the absolute neutron flux at the detector based on the measurement results of the neutron detector and its corresponding conversion factor.

[0071] The reactor neutron detector involved in this embodiment includes a neutron counting tube and an ionization chamber, wherein the neutron counting tube includes a BF3 neutron counting tube, 3He neutron counting tube, ionization chamber includes γ compensation ionization chamber, fission ionization chamber, etc. Neutron counting tube is often used to provide neutron counting signal to reactor critical extrapolation device, critical safety monitoring device, subcriticality measurement device, etc., for reactor criticality start-up process, reactor criticality safety monitoring, reactor subcriticality measurement, etc.; ionization chamber is often used to provide neutron current signal to reactor power measurement device, power protection device, cycle protection device and reactivity measurement instrument, etc., for reactor power measurement, overpower protection, short cycle protection, reactivity physical parameter measurement, etc.

[0072] like Figure 3 As shown, the method proposed in this embodiment specifically includes the following steps:

[0073] Step 100, using core physics calculation and analysis software to calculate the proportional relationship between the normalized calculated value of the neutron flux at the activation plate position and the normalized calculated value of the neutron flux at the neutron detector position.

[0074] In step 100, a theoretical calculation model is established based on the specific arrangement and material composition of the reactor core components and other components such as the activation plate, neutron detector, and reactor vessel, using core physics calculation and analysis software that can be finely modeled. The model establishment process is to accurately describe the fuel grid element, fuel assembly, core, core shroud, reflector, reactor vessel, etc. in sequence from inside to outside and from small to large, and accurately model the activation plate and neutron detector according to their actual size and spatial position, such as Figure 4 shown.

[0075] After the theoretical calculation model is established, the theoretical calculation model is calibrated and verified using the typical critical rod positions of the core obtained through actual reactor measurements. Taking a core as an example, Table 1 gives the theoretical calculation values ​​of the core proliferation factor under the typical critical rod positions and the corresponding critical rod positions. It can be seen from Table 1 that the maximum deviation of the theoretical calculation value is 2.8‰, and the calculation results of the established theoretical calculation model are quite accurate.

[0076] Table 1

[0077] Stick Position Measurement results Calculation results deviation(‰) Typical critical rod position A 1 0.99993 -0.07 Typical critical rod position B 1 1.00029 0.29 Typical critical rod position C 1 1.00176 1.76 Typical critical rod position D 1 0.99892 -1.08 Typical critical rod position E 1 1.00280 2.8 Typical critical rod position F 1 0.99917 -0.83 Typical critical rod position G 1 0.99941 -0.59

[0078] After establishing an accurate theoretical calculation model using core physics calculation and analysis software, the safety rods and other control rod positions of the theoretical calculation model are adjusted according to the actual critical rod position state of the reactor, so that the position states of all control rods in the theoretical calculation model are consistent with the actual measured rod position states of the reactor.

[0079] After the control rod position states of the theoretical calculation model are adjusted to be consistent, the initial parameters are set, including the number of calculation iterations and the number of particles calculated in a single time, and then parallel calculations are performed to obtain the normalized calculated values ​​of the neutron flux at the activation plate position and the normalized calculated values ​​of the neutron flux at the neutron detector position, and the calculation deviation is guaranteed to be controlled within 5%.

[0080] After calculating the normalized neutron flux calculated value at the activation plate position and the normalized neutron flux calculated value at the neutron detector position, the proportional relationship between the normalized neutron flux calculated value at the activation plate position and the neutron detector position is obtained, which can be expressed as:

[0081] α=Φ 归一活化 / Φ 归一探测

[0082] Among them, α represents the proportional relationship, Φ 归一活化 represents the normalized calculated value of the neutron flux at the activation plate position, Φ 归一探测 Represents the normalized calculated value of the neutron flux at the neutron detector location.

[0083] By calculating at multiple locations in the core, we can get Figure 5 Neutron flux distribution diagram shown.

[0084] Step 200, using the activation method to measure and obtain the absolute value of the neutron flux at the position of the activation plate, and according to the above proportional relationship, obtain the absolute value of the neutron flux at the position of the neutron detector.

[0085] Let the absolute value of the neutron flux at the activation plate be Φ 绝对活化 , the absolute value of the neutron flux at the neutron detector is Φ 绝对探测 According to the core power distribution characteristics of the reactor and the synchronous fluctuation characteristics of the core under the same state, we know that: α = Φ 归一活化 / Φ 归一探测 =Φ 绝对活化 / Φ 绝对探测 .

[0086] Based on this, the step 200 uses the activation method to measure the absolute neutron flux at the position of the activation plate. After the activation plate is irradiated in the core, the γ spectrometer and the absolute neutron flux measurement system are used to measure the absolute value of the neutron flux at the position of the activation plate. Therefore, according to the measured absolute value of the neutron flux at the position of the activation plate and the above relationship, the absolute value of the neutron flux at the position of the neutron detector can be obtained as follows:

[0087] Φ 绝对探测 =Φ 绝对活化 / α.

[0088] Step 300: calibrate and obtain a neutron detector conversion factor according to the neutron detector measurement result and the absolute value of the neutron flux at the position of the neutron detector, wherein the neutron detector conversion factor is the ratio of the neutron detector measurement result to the absolute value of the neutron flux at the position of the neutron detector.

[0089] The neutron detector conversion factor defined in this embodiment is the ratio of the neutron detector measurement result to the absolute value of the neutron flux at the location of the neutron detector. Let the neutron detector measurement result be R 测量 , the absolute value of the neutron flux at the neutron detector is Φ 绝对探测 , then the neutron detector conversion factor F 因子 =R 测量 / Φ 绝对探测 , where Φ 绝对探测 The unit is n / cm 2 ·s.

[0090] Among them, for BF3 neutron counting tube, 3 Neutron detectors of the He neutron counter type, such as neutron counter tubes, collect measurement results R 测量 is the number of counts, in units of n, then the neutron detector conversion factor F 因子 The unit is n / (n / cm 2 ·s).

[0091] For neutron detectors of ionization chamber types such as gamma compensation ionization chambers and fission ionization chambers, the measurement results collected by the neutron detectors R 测量 is the current value, in A, then the neutron detector conversion factor F 因子 The unit is A / (n / cm 2 ·s).

[0092] The calibration method proposed in this embodiment can obtain the conversion factor of the reactor neutron detector by calibration once, and then when the neutron detector is used to monitor the core state or measure important physical parameters of the core, the absolute measurement values ​​of the core absolute neutron flux and absolute power, which can characterize the actual operation state of the reactor, can be intuitively obtained. It is not necessary to use the traditional activation method to open the core for multiple irradiation experiments to measure the above parameters when the core layout or core state changes, thereby reducing the number of times the core is opened, saving time, saving manpower and material resources, reducing the impact of irradiation on personnel and avoiding the use of activation sheets. In addition, the calibration method proposed in this embodiment can also reduce damage to the reactor and supporting system equipment, and improve scientific research and production efficiency.

[0093] Based on the same technical concept as above, this embodiment also proposes a reactor neutron detector calibration system, such as Figure 6 As shown, the calibration system proposed in this embodiment specifically includes:

[0094] The model calculation module uses the core physics calculation and analysis software to calculate the proportional relationship between the normalized neutron flux calculation value at the activation plate position and the normalized neutron flux calculation value at the neutron detector position.

[0095] The measuring and calculating module measures and obtains the absolute value of the neutron flux at the position of the activation piece by using the activation method, and obtains the absolute value of the neutron flux at the position of the neutron detector according to the above proportional relationship.

[0096] And, a conversion module, which calibrates a neutron detector conversion factor according to the neutron detector measurement result and the absolute value of the neutron flux at the position of the neutron detector. The neutron detector conversion factor is the ratio of the neutron detector measurement result to the absolute value of the neutron flux at the position of the neutron detector.

[0097] Furthermore, the model calculation module of this embodiment may also include:

[0098] The model building unit establishes a theoretical calculation model based on the specific layout and material composition of the reactor core components and other components such as activation plates, neutron detectors, and reactor vessels, using core physics calculation and analysis software that can be finely modeled. The model building process follows the order from inside to outside and from small to large, and accurately describes the fuel grid elements, fuel assemblies, cores, core panels, reflectors, reactor vessels, etc., and accurately models the activation plates and neutron detectors according to their actual sizes and spatial positions.

[0099] The verification unit uses the typical critical rod positions in the core obtained through actual reactor measurements to check and verify the theoretical calculation model.

[0100] The adjusting unit adjusts the safety rods and other control rod positions of the theoretical calculation model according to the actual critical rod position state of the reactor, so that the rod position states of all control rods in the theoretical calculation model are consistent with the actual measured rod position states of the reactor.

[0101] And, an iterative calculation unit, which sets initial parameters, including the number of calculation iterations and the number of particles calculated in a single time, and then performs parallel calculations to obtain the normalized calculated value of the neutron flux at the activation plate position and the normalized calculated value of the neutron flux at the neutron detector position, thereby obtaining the proportional relationship between the normalized calculated values ​​of the neutron flux at the activation plate position and the neutron detector position.

[0102] It should be noted that the specific calculation process of the measurement calculation module and the conversion module in the above system is as described in the above steps 200 and 300, and will not be described in detail here.

[0103] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0104] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0105] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0106] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0107] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only the specific implementation method of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A reactor neutron detector calibration method, characterized in that: The calibration method comprises: The proportional relationship between the normalized calculated value of the neutron flux at the activation plate position and the normalized calculated value of the neutron flux at the neutron detector position is calculated using the core physics calculation and analysis software; The absolute value of the neutron flux at the position of the activation sheet is measured by the activation method, and the absolute value of the neutron flux at the position of the neutron detector is obtained according to the proportional relationship; Calibrate and obtain a neutron detector conversion factor according to the neutron detector measurement result and the absolute value of the neutron flux at the position of the neutron detector; The neutron detector conversion factor is the ratio of the neutron detector measurement result to the absolute value of the neutron flux at the position of the neutron detector.

2. A reactor neutron detector calibration method according to claim 1, characterized in that: The ratio between the normalized calculated value of the neutron flux at the activation plate position and the normalized calculated value of the neutron flux at the neutron detector position calculated by the core physics calculation and analysis software specifically includes: According to the specific arrangement and material composition of the reactor core components and activation plates, neutron detectors, and reactor vessels, a theoretical calculation model is established using the core physics calculation and analysis software; Using typical critical rod positions in the core obtained through actual reactor measurements to calibrate and verify the established theoretical calculation model; According to the actual critical rod position state of the reactor, adjust the safety rod and other control rod positions of the theoretical calculation model after verification and validation, so that the rod position states of all control rods in the theoretical calculation model are consistent with the actual measured rod position states of the reactor; After the rod position states are adjusted to be consistent, the initial parameters are set, and parallel calculations are performed to obtain the normalized calculated value of the neutron flux at the activation sheet position and the normalized calculated value of the neutron flux at the neutron detector position, and the calculation deviation is controlled within a preset range; A proportional relationship between a normalized calculated value of the neutron flux at the activation plate position and a normalized calculated value of the neutron flux at the neutron detector position is obtained.

3. A reactor neutron detector calibration method according to claim 2, characterized in that: The process of establishing the theoretical calculation model follows the order from inside to outside and from small to large, and accurately describes the fuel grid element, fuel assembly, core, core shroud, reflector layer, and reactor vessel, and accurately models the activation plate and neutron detector according to their actual size and spatial position.

4. A reactor neutron detector calibration method according to any one of claims 1 to 3, characterized in that: The method of measuring the absolute value of the neutron flux at the position of the activation sheet by the activation method, and obtaining the absolute value of the neutron flux at the position of the neutron detector according to the proportional relationship, specifically includes: After the activation sheet is irradiated in the core, the absolute value of the neutron flux at the position of the activation sheet is measured using a gamma spectrometer and an absolute neutron flux measurement system; According to the core power distribution characteristics of the reactor and the synchronous fluctuation characteristics of the core under the same state, it is obtained that the proportional relationship between the normalized calculated value of the neutron flux at the activation plate position and the normalized calculated value of the neutron flux at the neutron detector position is equal to the proportional relationship between the absolute value of the neutron flux at the activation plate position and the absolute value of the neutron flux at the neutron detector position; According to the absolute value of the neutron flux at the position of the activation sheet and the proportional relationship, the absolute value of the neutron flux at the position of the neutron detector is obtained.

5. A reactor neutron detector calibration method according to claim 4, characterized in that: For a neutron detector of the neutron counting tube type, the measurement result of the neutron detector is the number of counts.

6. A reactor neutron detector calibration method according to claim 4, characterized in that: For an ionization chamber type neutron detector, the measurement result of the neutron detector is a current value.

7. A reactor neutron detector calibration system, characterized in that: The calibration system comprises: A model calculation module, wherein the model calculation module uses core physics calculation and analysis software to calculate a proportional relationship between a normalized calculated value of neutron flux at an activation plate position and a normalized calculated value of neutron flux at a neutron detector position; A measurement and calculation module, wherein the measurement and calculation module measures the absolute value of the neutron flux at the position of the activation sheet by using an activation method, and obtains the absolute value of the neutron flux at the position of the neutron detector according to the proportional relationship; and, a conversion module, wherein the conversion module calibrates and obtains a neutron detector conversion factor according to the neutron detector measurement result and the absolute value of the neutron flux at the position of the neutron detector; The neutron detector conversion factor is the ratio of the neutron detector measurement result to the absolute value of the neutron flux at the position of the neutron detector.

8. A reactor neutron detector calibration system according to claim 7, characterized in that: The model calculation module also includes: A model building unit, wherein the model building unit uses the core physics calculation and analysis software to establish a theoretical calculation model according to the specific arrangement and material composition of the reactor core components and activation plates, neutron detectors, and reactor vessels; A verification unit, wherein the verification unit uses typical critical rod positions in the core obtained through actual reactor measurements to check and verify the established theoretical calculation model; An adjustment unit, wherein the adjustment unit adjusts the safety rods and other control rod positions of the theoretical calculation model after verification and validation according to the actual critical rod position state of the reactor, so that the rod position states of all control rods in the theoretical calculation model are consistent with the actual measured rod position states of the reactor; And, an iterative calculation unit, which sets initial parameters and performs parallel calculations to obtain a normalized calculated value of the neutron flux at the activation plate position and a normalized calculated value of the neutron flux at the neutron detector position, thereby obtaining a proportional relationship between the normalized calculated value of the neutron flux at the activation plate position and the normalized calculated value of the neutron flux at the neutron detector position.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

Images