Analysis method and system of nuclear reactor fission chamber detector

Abstract

The invention relates to an analysis method and system for a fission chamber detector of a nuclear reactor. The method comprises the following steps: constructing a simulation model according to the structure of the fission chamber detector to be detected and a Monte Carlo method; wherein when neutrons are injected into the simulation model, fission reaction is simulated, and the number of fission fragments in the fission reaction process is calculated; injecting neutrons into the simulation model through a preset neutron source to determine the number of fission fragments; determining the neutron fluence rate of the simulation model in the process of simulating the fission reaction; and determining the sensitivity of the fission chamber detector to be detected according to the number of the fission fragments and the neutron fluence rate. The simulation model capable of replacing the fission chamber detector to be detected to simulate the fission reaction is constructed based on the Monte Carlo method, and the sensitivity of the fission chamber detector to the thermal neutrons can be accurately detected.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear measurement detectors in nuclear power plants, and in particular to an analysis method and system for a nuclear reactor fission chamber detector. Background Art

[0002] Fission chamber detectors are devices used to measure and detect nuclear fission reactions. They are commonly used in the nuclear energy sector, radioactive material research, and nuclear reactor monitoring. By measuring the number and characteristics of fission reactions, fission chamber detectors can assess the fission properties and radioactivity levels of nuclear materials, which is of great significance to nuclear energy safety and radiation monitoring. Thermal neutron sensitivity is one of the key indicators used to evaluate the performance of fission chamber detectors. Currently, nuclear power plants urgently need a solution to accurately analyze the thermal neutron sensitivity of fission chamber detectors. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an analysis method and system for a nuclear reactor fission chamber detector.

[0004] The technical solution adopted by the present invention to solve the technical problem is to construct an analysis method for a nuclear reactor fission chamber detector for analyzing the neutron sensitivity of the fission chamber detector, the analysis method comprising:

[0005] A simulation model is constructed based on the structure of the fission chamber detector to be tested and the Monte Carlo method; wherein the simulation model simulates a fission reaction when injected with neutrons and calculates the number of fission fragments during the fission reaction;

[0006] Injecting neutrons into the simulation model through a preset neutron source to determine the number of fission fragments;

[0007] Determining a neutron injection rate of the simulation model during a simulated fission reaction;

[0008] The sensitivity of the detector of the fission chamber to be tested is determined according to the number of fission fragments and the neutron fluence rate.

[0009] Preferably, the step of establishing a simulation model according to the structure of the fission chamber detector to be tested and the Monte Carlo method includes:

[0010] A geometric structure model constructed according to the ionization chamber of the fission chamber detector to be tested;

[0011] The geometric structure model is configured with a function capable of simulating a fission physical process by using a Monte Carlo method to obtain the fission physical model; the fission physical process includes a fission reaction based on a neutron source, and decay, strong interaction, and electromagnetic interaction occurring during the fission reaction;

[0012] A fission fragment statistics function is added to the fission physics model to obtain the simulation model.

[0013] Preferably, the fission fragment statistics function includes:

[0014] Acquiring a plurality of pulse signals outputted during a fission reaction simulated by the simulation model;

[0015] performing truncation processing on each of the pulse signals to determine the number of fission fragments;

[0016] The truncation process includes: determining, in each of the pulse signals, the number of pulse signals having signal energy greater than a predetermined energy threshold, and determining the number of pulse signals as the number of fission fragments.

[0017] Preferably, the predetermined energy threshold ranges from 5 MeV to 7 MeV.

[0018] Preferably, the step of constructing a geometric structure model according to the ionization chamber of the fission chamber detector to be tested comprises:

[0019] Obtaining component configuration information of the fission chamber detector to be tested; wherein the fission chamber detector to be tested includes a plurality of structural components, and the structural configuration information includes specification parameters of each of the structural components and connection relationships between the structural components;

[0020] Constructing a plurality of simulation parts corresponding to each of the structural parts according to the specification parameters of each of the structural parts;

[0021] The geometric structure model is constructed according to the connection relationship and the multiple simulation parts.

[0022] Preferably, the plurality of simulation parts include:

[0023] Outer cylinder simulation part;

[0024] A shell simulation part, the shell simulation part is cylindrical and is arranged in the outer cylinder simulation part, and a cavity is provided in the shell simulation part;

[0025] A positive electrode simulation component, the positive electrode simulation component is cylindrical and is disposed in the cavity of the shell simulation component;

[0026] a first uranium-plated layer, wherein the first uranium-plated layer is plated on an inner wall of the positive electrode simulation component;

[0027] A signal electrode simulation component, which is cylindrical and disposed within the cylinder of the positive electrode simulation component;

[0028] A second uranium plating layer is plated on the outer wall of the signal pole simulation component, and the second uranium plating layer also cooperates with the cavity of the shell simulation component to form a closed ionization chamber simulation component. When the ionization chamber simulation component is injected with the neutron source, the first uranium plating layer and the second uranium plating layer have a certain probability of undergoing fission reaction with neutrons.

[0029] Preferably, the neutron source is cylindrical; the step of injecting neutrons into the simulation model through the preset neutron source comprises:

[0030] Acquiring neutron source setting parameters, wherein the neutron source setting parameters include an incident angle and a neutron energy value;

[0031] placing the simulation model inside the cylinder of the neutron source;

[0032] Setting the direction in which the neutron source emits neutrons according to the incident angle;

[0033] The neutron source is controlled to output neutrons according to the neutron energy value.

[0034] Preferably, the neutron energy value is 0.0253 eV; and / or

[0035] The incident angle is isotropic scattering.

[0036] Preferably, the step of determining the sensitivity of the fission chamber detector to be tested according to the number of fission fragments and the neutron fluence rate comprises:

[0037] Get correction parameters;

[0038] Correcting the number of fission fragments according to the correction parameter to obtain a corrected number of fission fragments;

[0039] The sensitivity is obtained by dividing the corrected number of fission fragments by the neutron fluence rate.

[0040] In addition, the present invention also constructs an analysis system for a nuclear reactor fission chamber detector, comprising:

[0041] A model simulation unit, configured to construct a simulation model based on the structure of the fission chamber detector to be tested and the Monte Carlo method; wherein the simulation model simulates a fission reaction when neutrons are injected and calculates the number of fission fragments during the fission reaction;

[0042] a neutron source injection unit, configured to inject neutrons into the simulation model via a preset neutron source and determine the number of fission fragments;

[0043] A fluence rate determination unit is used to determine the neutron fluence rate of the simulation model during the simulation of the fission reaction; and

[0044] A sensitivity determination unit is used to determine the sensitivity of the fission chamber detector to be tested according to the number of fission fragments and the neutron fluence rate.

[0045] The technical solution of the present invention is based on the Monte Carlo method to construct a simulation model that can replace the fission chamber detector to be tested to simulate the fission reaction. It can not only accurately detect the sensitivity of the fission chamber detector to thermal neutrons, providing important data basis for further optimization and improvement of the fission chamber detector, but also has the advantages of high safety and good flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0047] Figure 1 is a flowchart of a method for analyzing a nuclear reactor fission chamber detector in some embodiments of the present invention;

[0048] Figure 2 is a flowchart of a procedure for establishing a simulation model in some embodiments of the present invention;

[0049] Figure 3 is a flowchart of step S11 in some embodiments of the present invention;

[0050] Figure 4 is a schematic structural diagram of a fission chamber detector in some embodiments of the present invention;

[0051] Figure 5 is a schematic structural diagram of a neutron source in some embodiments of the present invention;

[0052] Figure 6 It is a structural block diagram of an analysis system of a nuclear reactor fission chamber detector in some embodiments of the present invention. DETAILED DESCRIPTION

[0053] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0054] It should be noted that the flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all content and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0055] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0056] Figure 1 This is a flowchart of a method for analyzing nuclear reactor fission chamber detectors in some embodiments of the present invention. This method can accurately analyze the sensitivity of fission chamber detectors to thermal neutrons (hereinafter referred to as neutrons), providing data for further optimization and improvement of fission chamber detectors.

[0057] See Figure 1 The analysis method of the nuclear reactor fission chamber detector may include step S1, step S2, step S3 and step S4.

[0058] Step S1 includes: constructing a simulation model based on the structure of the fission chamber detector to be tested and the Monte Carlo method; wherein the simulation model simulates a fission reaction when neutrons are injected, and calculates the number of fission fragments during the fission reaction.

[0059] It is easy to understand that the role of the simulation model is to replace the fission chamber detector to be tested to perform simulated fission reaction tests, realizing the measurement of the sensitivity of the fission chamber detector to thermal neutrons using simulation technology. Therefore, there is no need to conduct complicated and equipment-intensive tests on site or in the laboratory. The test efficiency is high, and there is no radiation risk for the workers. It has great advantages in terms of safety, flexibility and testing costs.

[0060] Figure 2 : is a flowchart of a program for establishing a simulation model in some embodiments of the present invention. In some embodiments, the simulation model can be established by executing Figure 2 The simulation model is established by performing steps S11 to S13.

[0061] Step S11 includes constructing a geometric model of the ionization chamber of the fission chamber detector under test. Because different fission chamber detectors have different structures, this step constructs a geometric model consistent with the actual structure of the fission chamber detector under test. This ensures that the functionality of the subsequently constructed simulation model is as close as possible to, or even equivalent to, the actual functionality of the fission chamber detector under test, which is crucial for improving analytical accuracy.

[0062] In some embodiments, by executing Figure 3 The geometric structure model is constructed by performing steps S111 to S113.

[0063] Step S111 includes: obtaining component setting information of the fission chamber detector to be tested; wherein, the fission chamber detector to be tested includes multiple structural parts, and the structural setting information includes specification parameters of each structural part (which may include the material, size, composition, electrical properties, nuclear properties, etc. of the structural part), as well as the connection relationship between the structural parts.

[0064] In some embodiments, as Figure 4 As shown, the fission chamber detector mainly includes an outer tube 71, an outer shell 72, a positive electrode 73, a uranium coating on the positive electrode (not shown), a positive electrode ceramic 74, a signal electrode 75, a uranium coating on the signal electrode (not shown), a signal electrode ceramic 76, an ionization chamber base 77, a lower insulating ceramic 78, an end cover 79, a cable 80, an outer tube base 81 and a working gas (not shown) and other structural parts. Figure 4 As can be seen, the fission chamber detector has a relatively complex structure. A 100% simulation would be labor-intensive and time-consuming. However, the ionization chamber 82 of the fission chamber detector is the structural component primarily relevant to the fission reaction. Therefore, it is advisable to simulate and construct only this ionization chamber 82 to obtain the geometric structure model described above, which helps simplify the geometric simulation workload. Of course, to further improve analytical accuracy, a 100% simulation of the fission chamber detector can be achieved, which would provide even greater analytical accuracy.

[0065] Among them, the main structural components of the ionization chamber 82 that constructs the ionization chamber include an outer cylinder 71, an outer shell 72, a positive electrode 73, a uranium plating layer on the positive electrode, a positive electrode ceramic 74, a signal electrode 75 and a uranium plating layer on the signal electrode.

[0066] Taking a certain fission chamber detector in a nuclear power plant as an example, the material of the outer tube 71 is titanium (density can be 4.507g / cm 3 ), the dimensions of the outer cylinder 71 include: outer diameter is 70mm, thickness is 1mm. The material of the outer shell 72 is titanium (density can be 4.507g / cm 3 ), the dimensions of the housing 72 include: outer diameter is 50mm, thickness is 1mm. The material of the positive electrode 73 is aluminum (density can be 2.7g / cm 3 ), the dimensions of the positive electrode 73 include: outer diameter is 43mm, thickness is 1mm. The material of the uranium coating on the positive electrode is UO2, and the dimensions of the uranium coating on the positive electrode include: thickness is 400μg / cm 2 The material of the signal electrode 75 is aluminum (density can be 2.7g / cm 3 ), the dimensions of the signal electrode 75 include: outer diameter is 37mm, thickness is 1mm. The material of the uranium coating on the signal electrode is UO2, and the dimensions of the uranium coating on the signal electrode include: thickness is 400μg / cm 2The composition of the working gas is Ar+N2. The length of the sensitive area of the fission chamber detector is 258mm. In addition, the specific connection structure of the above-mentioned structural parts can be referred to Figure 4 , I will not go into details here.

[0067] Step S112 includes: constructing a plurality of simulation components corresponding to each structural component according to the specification parameters of each structural component. In this step, each simulation component can be constructed by simulation software (such as MCNP software (Monte Carlo N Particle Transport Code)).

[0068] Specifically, the multiple simulation parts may include an outer cylinder simulation part, a shell simulation part, a positive electrode simulation part, a first uranium plating layer, a signal electrode simulation part, a second uranium plating layer and simulated working gas.

[0069] The outer cylinder simulation part is cylindrical in shape. The material and size of the outer cylinder simulation part are consistent with the material and size of the outer cylinder 71 in the fission chamber detector to be tested.

[0070] The shell simulation part is cylindrical and is arranged inside the outer cylinder simulation part. The shell simulation part has a cavity. The material and size of the shell simulation part are consistent with the material and size of the shell 72 in the fission chamber detector to be tested.

[0071] The positive electrode simulation part is cylindrical and is arranged in the cylinder of the outer shell simulation part. The material and size of the positive electrode simulation part are consistent with the material and size of the positive electrode 73 in the fission chamber detector to be tested.

[0072] The first uranium plating layer is plated on the inner wall of the positive electrode simulation component. The material and size of the first uranium plating layer are consistent with the material and size of the uranium plating layer on the positive electrode in the fission chamber detector to be tested.

[0073] The signal electrode simulation piece is cylindrical and is arranged in the cylinder of the positive electrode simulation piece. The material and size of the signal electrode simulation piece are consistent with the material and size of the signal electrode 75 in the fission chamber detector to be tested.

[0074] A second uranium coating is applied to the outer wall of the signal electrode dummy. The second uranium coating also cooperates with the cavity of the outer shell dummy to form a closed ionization chamber dummy. When a neutron source is injected into the ionization chamber dummy, the first and second uranium coatings have a certain probability of undergoing a fission reaction with the neutrons. The material and dimensions of the second uranium coating are consistent with those of the uranium coating on the signal electrode in the fission chamber detector to be tested.

[0075] A simulated working gas is injected into the cavity of the shell simulation part, and the composition of the simulated working gas is consistent with the composition of the working gas in the fission chamber detector to be tested.

[0076] Step S113 includes: constructing a geometric structure model based on the connection relationship and multiple simulation parts. In this step, the specific connection relationship of each structural part of the fission chamber detector to be tested can be obtained from the manufacturer, and then the geometric simulation software can be used to construct a geometric structure model based on the connection relationship. Figure 4 An ionization chamber simulation piece with the same structure as shown is used to obtain the geometric structure model.

[0077] Step S12 includes configuring the geometric structure model with functions capable of simulating fission physical processes using a Monte Carlo method to obtain a fission physics model. The fission physical processes may include fission reactions based on a neutron source, as well as decay, strong interactions, and electromagnetic interactions occurring during the fission reactions.

[0078] In this step, the geometric structure model can be configured with functions capable of simulating the fission physical processes based on the relevant physical processes using GEANT4 and Garfield software. Taking the fission reaction in an ionization chamber as an example, the specific physical processes include: when neutrons are injected into the ionization chamber, the neutrons will produce ionizing collisions with the working gas, gradually losing energy before being stopped. During the collision process, the working gas molecules are ionized or excited, generating a large number of particle pairs consisting of electrons and positive ions along the path of the fission fragments. The ionization process also includes two stages: ionization caused by direct collisions between the incident neutrons and gas molecules, and ionization caused by high-speed electrons ejected by the collision. Furthermore, during the ionization process, particles such as leptons, baryons, bosons, ions, muons, and short-lived particles will also undergo physical processes such as decay, strong interactions, and electromagnetic interactions. The detailed physical processes of decay, strong interactions, and electromagnetic interactions can be referenced in the prior art and will not be elaborated here.

[0079] In addition, the detection principle of the fission chamber detector or simulation model to be tested is: since an electric field is generated between the signal electrode and the positive electrode in the ionization chamber, the generated electrons and positive ions will drift under the action of the electric field and finally be collected on the electrodes. Due to electrostatic induction, charges will be induced on the electrodes and change with their drift, forming an ionization current in the output circuit. The intensity of the current is determined by factors such as the number of ion pairs collected. Therefore, the response signal output by the fission chamber detector or simulation model to be tested can represent the number of fission fragments.

[0080] In this step, the geometric structure model is preferably configured using Garfield software to enable fission reactions based on a neutron source. The Garfield software package, developed by Rob Veenhof of CEAN, is a simulation program for detailed two-dimensional and three-dimensional gas detectors. This software allows for detailed simulation of the detector's electric field distribution, working gas parameters, primary ionization of charged particles, drift and diffusion of primary ionized electrons in the gas, and the induced signal.

[0081] GEANT4 software is preferably used to configure the geometry model with features that can account for decay, strong interactions, and electromagnetic interactions that occur during fission reactions. The Geant4 (Geometry and Tracking) toolkit is a large-scale Monte Carlo software toolkit based on the C++ language, jointly developed by CERN and the High Energy Accelerator Research Organization (KEF), Japan, and is primarily used for particle transport simulations.

[0082] Step S13 includes: adding a fission fragment statistics function to the fission physics model to obtain a simulation model.

[0083] In some embodiments, the fission fragment statistics function may include: obtaining multiple pulse signals output by a simulation model during the fission reaction simulation; truncation processing is performed on each pulse signal to determine the number of fission fragments; wherein the truncation processing includes: in each pulse signal, determining the number of pulse signals whose signal energy is greater than a predetermined energy threshold, and determining the number of pulse signals as the number of fission fragments.

[0084] It should be noted that the simulation model in the present invention can simulate the function of the fission chamber detector to be tested, so it will simulate the fission reaction based on the injected neutrons and output a response signal (composed of multiple pulse signals) that can characterize the number of fission fragments. 235 U has α decay with energy of 4.22MeV to 4.60MeV, which generates interference or noise to the response signal and has an adverse effect on the counting of the number of fission fragments. Therefore, the fission chamber detector will identify the corresponding α decay through the threshold when outputting the statistical signal. Accordingly, this embodiment truncates each pulse signal to filter out the pulse signals with signal energy less than the predetermined energy threshold, thereby eliminating the influence of α decay, thereby improving the accuracy of fission fragment statistics.

[0085] In order to ensure the screening effect, the predetermined energy threshold should be slightly larger than the maximum energy of α decay. For example, the predetermined energy threshold may be in the range of 5 MeV to 7 MeV, preferably 6 MeV.

[0086] It is easy to understand that the ionization chamber simulation composed of various simulation components not only has the same structure as the ionization chamber of the fission chamber detector to be tested, but also has the same sensitive area length of 258 mm, and also has the function of undergoing the same fission physical process. Therefore, the ionization chamber simulation can replace the fission chamber detector to be tested to simulate fission reactions, and has the advantage of high accuracy.

[0087] Step S2 includes: injecting neutrons into the simulation model through a preset neutron source to determine the number of fission fragments.

[0088] In one embodiment, see Figure 5 The neutron source 91 may be cylindrical. Accordingly, the step of injecting neutrons into the simulation model using the preset neutron source may include: obtaining neutron source setting parameters, wherein the neutron source setting parameters include an incident angle and a neutron energy value; placing the simulation model inside the cylindrical body of the neutron source; setting the direction of neutron emission from the neutron source according to the incident angle; and controlling the neutron output of the neutron source according to the neutron energy value. The neutron energy value may be 0.0253 eV, and the incident angle may be isotropic scattering.

[0089] It should be noted that isotropic scattering means that the probability of neutron emission in all directions is consistent, including parallel, vertical, oblique (along the radial direction of the neutron source) and other directions. The purpose of setting the incident angle to isotropic scattering is to enable the simulation model to be injected with neutrons in different directions, which is close to the actual working conditions of the fission chamber detector to be tested.

[0090] Further, see Figure 5 The simulation model 90 can be placed at the center of the tube of the neutron source 91 so that the probability of the simulation model 90 being injected with neutrons from all directions can be kept as consistent as possible, so as to further approach the actual working conditions of the fission chamber detector to be tested.

[0091] In order to control the neutron injection rate, such as Figure 5 As shown, a moderator 92 may be provided between the neutron source 91 and the simulation model 90. It should be noted that the neutron source 91 and the moderator 92 in step S2 are both simulation components established by existing simulation software.

[0092] Step S3 includes determining the neutron fluence rate of the simulation model during the simulated fission reaction. Specifically, during the process of the neutron source injecting neutrons into the simulation model, software counts the number of neutrons entering the maximum cross-sectional area corresponding to the simulation model 90. The neutron fluence rate is then calculated by dividing the number of neutrons by the maximum cross-sectional area. More specifically, the Monte Carlo method can be used to set the probability of the neutron source emitting neutrons in all directions inward to be equal. The maximum cross-sectional area of the simulation model is then used as input, and the simulation model and the neutron source are set to be centrally symmetric. Simulation can then be performed to calculate the number of neutrons.

[0093] Step S4 includes: determining the sensitivity of the detector of the fission chamber to be tested according to the number of fission fragments and the neutron fluence rate.

[0094] In some embodiments, the sensitivity of the fission chamber detector to be tested can be determined by performing the following steps: obtaining correction parameters; correcting the number of fission fragments according to the correction parameters to obtain the corrected number of fission fragments; calculating the quotient of the corrected number of fission fragments divided by the neutron injection rate to obtain the sensitivity.

[0095] In this embodiment, the correction parameter can be a preset value. The number of fission fragments after correction can be calculated by multiplying the number of fission fragments by the correction parameter. The correction parameter is generally set by the staff based on actual conditions and experience, and the correction parameter is related to the probability of fission fragments entering the ionization region, 235 It is related to correction factors such as the actual enrichment of U.

[0096] In some embodiments, as Figure 1 As shown, the analysis method of the nuclear reactor fission chamber detector may further include step S5 and step S6.

[0097] Step S5 includes: determining whether the sensitivity is greater than or equal to a set threshold. The setting range of the set threshold can be 0.2 cps / n·cm 2 ·s -1 to 0.4cps / n·cm 2 ·s -1 The threshold is preferably set at 0.3 cps / n·cm 2 ·s -1 .

[0098] Step S6 includes: when the sensitivity is greater than or equal to the set threshold, outputting a qualified signal; when the sensitivity is less than the set threshold, outputting a failed signal.

[0099] The technical solution of the present invention is based on the Monte Carlo method to construct a simulation model that can replace the fission chamber detector to be tested to simulate the fission reaction. It can not only accurately detect the sensitivity of the fission chamber detector to thermal neutrons, providing important data basis for further optimization and improvement of the fission chamber detector, but also has the advantages of high safety and good flexibility.

[0100] See also Figure 6 The present invention also provides an analysis system for a nuclear reactor fission chamber detector, which may include a model simulation unit, a neutron source injection unit, a fluence rate determination unit, and a sensitivity determination unit.

[0101] The model simulation unit is used to construct a simulation model based on the structure of the fission chamber detector to be tested and the Monte Carlo method. This simulation model simulates the fission reaction when injected with neutrons and calculates the number of fission fragments produced during the fission reaction. The detailed process of constructing the simulation model by the model simulation unit can be found above and will not be detailed here.

[0102] The neutron source injection unit is used to inject neutrons into the simulation model using a preset neutron source and determine the number of fission fragments. It should be noted that the construction method of the neutron source and the control method of the neutron injection unit (including the incident angle and neutron energy value) can be found above and will not be repeated here.

[0103] The neutron fluence rate determination unit is used to determine the neutron fluence rate of the simulation model during the fission reaction simulation. It should be noted that the calculation method of the neutron fluence rate can be referred to above and will not be repeated here.

[0104] The sensitivity determination unit is used to determine the sensitivity of the fission chamber detector to be tested according to the number of fission fragments and the neutron fluence rate. It should be noted that the calculation method of the sensitivity of the fission chamber detector to be tested can be referred to above and will not be repeated here.

[0105] In some embodiments, the analysis system of the nuclear reactor fission chamber detector may further include a judgment unit and a result output unit.

[0106] The judgment unit is used to judge whether the sensitivity is greater than or equal to the set threshold. The setting range of the set threshold can be 0.2cps / n·cm 2 ·s -1 to 0.4cps / n·cm 2 ·s -1 The threshold is preferably set at 0.3 cps / n·cm 2 ·s -1 .

[0107] The result output unit is used to output a qualified signal when the sensitivity is greater than or equal to the set threshold, and output a failed signal when the sensitivity is less than the set threshold.

[0108] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0109] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0110] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0111] It is understandable that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, all of which fall within the scope of protection of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of coverage of the claims of the present invention.

Claims

1. A method for analyzing a nuclear reactor fission chamber detector, for analyzing the neutron sensitivity of a fission chamber detector, characterized in that: The analytical method includes: A simulation model is constructed based on the structure of the fission chamber detector to be tested and the Monte Carlo method; wherein the simulation model simulates a fission reaction when injected with neutrons and calculates the number of fission fragments during the fission reaction; Injecting neutrons into the simulation model through a preset neutron source to determine the number of fission fragments; Determining a neutron injection rate of the simulation model during a simulated fission reaction; The sensitivity of the detector of the fission chamber to be tested is determined according to the number of fission fragments and the neutron fluence rate.

2. The analysis method of a nuclear reactor fission chamber detector according to claim 1, characterized in that: The step of establishing a simulation model based on the structure of the fission chamber detector to be tested and the Monte Carlo method includes: Constructing a geometric structure model according to the ionization chamber of the fission chamber detector to be tested; The geometric structure model is configured with a function capable of simulating a fission physical process by using a Monte Carlo method to obtain the fission physical model; the fission physical process includes a fission reaction based on a neutron source, and decay, strong interaction, and electromagnetic interaction occurring during the fission reaction; A fission fragment statistics function is added to the fission physics model to obtain the simulation model.

3. The analysis method of a nuclear reactor fission chamber detector according to claim 2, characterized in that: The fission fragment statistics function includes: Acquiring a plurality of pulse signals outputted during a fission reaction simulated by the simulation model; performing truncation processing on each of the pulse signals to determine the number of fission fragments; The truncation process includes: determining, in each of the pulse signals, the number of pulse signals having signal energy greater than a predetermined energy threshold, and determining the number of pulse signals as the number of fission fragments.

4. The analysis method of a nuclear reactor fission chamber detector according to claim 3, characterized in that: The predetermined energy threshold ranges from 5 MeV to 7 MeV.

5. The analysis method of a nuclear reactor fission chamber detector according to claim 2, characterized in that: The step of constructing a geometric structure model according to the ionization chamber of the fission chamber detector to be tested comprises: Obtaining component configuration information of the fission chamber detector to be tested; wherein the fission chamber detector to be tested includes a plurality of structural components, and the structural configuration information includes specification parameters of each of the structural components and connection relationships between the structural components; Constructing a plurality of simulation parts corresponding to each of the structural parts according to the specification parameters of each of the structural parts; The geometric structure model is constructed according to the connection relationship and the multiple simulation parts.

6. The analysis method for a nuclear reactor fission chamber detector according to claim 5, characterized in that: The plurality of simulation parts include: Outer cylinder simulation part; A shell simulation part, the shell simulation part is cylindrical and is arranged in the outer cylinder simulation part, and a cavity is provided in the shell simulation part; A positive electrode simulation component, the positive electrode simulation component is cylindrical and is disposed in the cavity of the shell simulation component; a first uranium-plated layer, wherein the first uranium-plated layer is plated on an inner wall of the positive electrode simulation component; A signal electrode simulation component, which is cylindrical and disposed within the cylinder of the positive electrode simulation component; A second uranium plating layer is plated on the outer wall of the signal pole simulation component, and the second uranium plating layer also cooperates with the cavity of the shell simulation component to form a closed ionization chamber simulation component. When the ionization chamber simulation component is injected with the neutron source, the first uranium plating layer and the second uranium plating layer have a certain probability of undergoing fission reaction with neutrons.

7. The analysis method for a nuclear reactor fission chamber detector according to any one of claims 1 to 6, characterized in that: The neutron source is cylindrical; the step of injecting neutrons into the simulation model through the preset neutron source includes: Acquiring neutron source setting parameters, wherein the neutron source setting parameters include an incident angle and a neutron energy value; placing the simulation model inside the cylinder of the neutron source; Setting the direction in which the neutron source emits neutrons according to the incident angle; The neutron source is controlled to output neutrons according to the neutron energy value.

8. The analysis method for a nuclear reactor fission chamber detector according to claim 7, characterized in that: The neutron energy value is 0.0253 eV; and / or The incident angle is isotropic scattering.

9. The analysis method for a nuclear reactor fission chamber detector according to claim 8, characterized in that: The step of determining the sensitivity of the fission chamber detector to be tested according to the number of fission fragments and the neutron fluence rate comprises: Get correction parameters; Correcting the number of fission fragments according to the correction parameter to obtain a corrected number of fission fragments; The sensitivity is obtained by dividing the corrected number of fission fragments by the neutron fluence rate.

10. An analysis system for a nuclear reactor fission chamber detector, characterized in that: include: A model simulation unit, configured to construct a simulation model based on the structure of the fission chamber detector to be tested and the Monte Carlo method; wherein the simulation model simulates a fission reaction when neutrons are injected and calculates the number of fission fragments during the fission reaction; a neutron source injection unit, configured to inject neutrons into the simulation model via a preset neutron source and determine the number of fission fragments; A fluence rate determination unit is used to determine the neutron fluence rate of the simulation model during the simulation of the fission reaction; and A sensitivity determination unit is used to determine the sensitivity of the fission chamber detector to be tested according to the number of fission fragments and the neutron fluence rate.

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