Ex-core nuclear detection device and system and detection data processing method thereof

Abstract

The invention discloses an ex-core nuclear detection device and system and a detection data processing method thereof.The ex-core nuclear detection device comprises a plurality of source range detector assemblies, a plurality of middle range detector assemblies and a plurality of power range detector assemblies which can be fixed to the boundary of a pressure vessel of a reactor to be detected; the plurality of source range detector assemblies, the plurality of middle range detector assemblies and the plurality of power range detector assemblies all comprise multi-layer detection structures; wherein the multi-layer detection structure comprises a detector body, a moderated material structural body and an aluminum shell which are arranged layer by layer from inside to outside. According to the out-of-pile nuclear detection device, not only can the detection sensitivity of various types of detector assemblies be improved by additionally arranging the moderated material structural body and the aluminum shell on the detector assembly, but also the aluminum shell can prevent the moderated material of the moderated material structural body from deforming in a high-irradiation environment.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear measurement components of a nuclear instrument system, and in particular to an out-of-core nuclear detection device, a system and a detection data processing method thereof. Background Art

[0002] The extra-core nuclear detection system (RPN, also known as the nuclear instrumentation system) characterizes the nuclear power of the reactor core fuel by setting up a series of neutron detector assemblies outside the reactor pressure vessel and measuring the neutron reaction of the core through the detector assemblies. During the first fuel loading of a nuclear power plant unit, in order to meet the minimum neutron flux monitoring requirements specified in the standard, a neutron source (a device that can release neutrons) is required to activate the new fuel. Commercial reactor neutron sources include primary neutron sources (typically Cf252) and secondary neutron sources (typically Sb-Be). The first-generation neutron source has a long half-life and high intensity, but is expensive; the secondary neutron source is baked during the operation of the existing unit core, and the price is relatively low, but the half-life is short and the intensity decays quickly.

[0003] At present, existing reactor types use secondary neutron sources for reactor fuel loading. Secondary neutron sources decay faster than primary neutron sources and have a short effective loading time. In order to ensure that the secondary neutron source loading can be effectively used for loading for as long as possible, the detection performance of the extra-core nuclear measurement detector assembly needs to be guaranteed.

[0004] The existing CPR1000 reactor technology RPN system design and reactor core are relatively mature and stable. The RPN system detector adopts a component design. The sensitivity of the bare detector in the existing reactor is low. Without performance improvement, it cannot meet the sensitivity requirements of the secondary source loading of the new reactor. More specifically, the existing RPN system has the following technical defects:

[0005] 1) Without systematic modeling and analysis, the source range detector has low sensitivity and cannot be applied to new reactor loading monitoring;

[0006] 2) The intermediate range is the compensated ionization chamber solution, which does not meet the RG1.97 long-term monitoring requirements after an accident; RG1.97 refers to RG1.97 "Criteria for Accident Monitoring Instruments in Nuclear Power Plants". Summary of the invention

[0007] The embodiments of the present invention provide an off-core nuclear detection device, a system and a detection data processing method thereof, aiming to solve the problem that the source range detector in the nuclear instrument system in the prior art has low sensitivity and cannot be applied to new reactor type charging monitoring.

[0008] In the first aspect, an embodiment of the present invention provides an extra-core nuclear detection device, which includes a plurality of source range detector assemblies, a plurality of intermediate range detector assemblies and a plurality of power range detector assemblies, and the plurality of source range detector assemblies, the plurality of intermediate range detector assemblies and the plurality of power range detector assemblies can all be fixed at the boundary of the pressure vessel of the reactor to be detected; the plurality of source range detector assemblies, the plurality of intermediate range detector assemblies and the plurality of power range detector assemblies all include a multi-layer detection structure; wherein the multi-layer detection structure includes a detector body, a moderation material structure and an aluminum shell arranged layer by layer from the inside to the outside.

[0009] In a second aspect, an embodiment of the present application further provides an extra-core nuclear detection system, which includes an extra-core nuclear detection device as described in the first aspect above, and also includes a penetration piece and a nuclear instrument cabinet; wherein the extra-core nuclear detection device is connected to the nuclear instrument cabinet via the penetration piece.

[0010] In a third aspect, an embodiment of the present application further provides a detection data processing method of an ex-core detection system, which is applied to the ex-core detection system as described in the second aspect above; the detection data processing method of the ex-core detection system includes:

[0011] Obtaining a first theoretical count rate of the reference detector under the secondary source loading energy spectrum, and obtaining a detection performance ratio of the source range detector assembly and the reference detector in the ex-core nuclear detection system under an on-site plutonium-beryllium source test;

[0012] determining a second theoretical count rate of the source range detector assembly based on the first theoretical count rate and the detection performance ratio;

[0013] Obtaining an estimated probability rate of the source range detector assembly when the neutron source of the reactor to be monitored is in a preset state;

[0014] Based on the comparison of the second theoretical count rate with the estimated count rate, a currently calculated count rate of the source range detector assembly is determined.

[0015] The embodiment of the present invention provides an ex-core nuclear detection device, a system and a detection data processing method thereof. The ex-core nuclear detection device includes a plurality of source range detector assemblies, a plurality of intermediate range detector assemblies and a plurality of power range detector assemblies, and the plurality of source range detector assemblies, the plurality of intermediate range detector assemblies and the plurality of power range detector assemblies can be fixed at the boundary of the pressure vessel of the reactor to be detected; the plurality of source range detector assemblies, the plurality of intermediate range detector assemblies and the plurality of power range detector assemblies all include a multi-layer detection structure; wherein the multi-layer detection structure includes a detector body, a moderator material structure and an aluminum shell arranged layer by layer from the inside to the outside. The above-mentioned ex-core nuclear detection device can not only improve the detection sensitivity of various types of detector assemblies by adding a moderator material structure and an aluminum shell to the detector assembly, but also the aluminum shell can prevent the moderator material of the moderator material structure from deforming in a high irradiation environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0017] Figure 1 A schematic block diagram of an out-of-core nuclear detection device provided by an embodiment of the present invention;

[0018] Figure 2 A schematic cross-sectional view of a multi-layer detection structure in an out-of-core nuclear detection device provided by an embodiment of the present invention;

[0019] Figure 3 A schematic cross-sectional structure diagram of a first multi-layer detection structure in an out-of-core nuclear detection device provided by an embodiment of the present invention;

[0020] Figure 4 A schematic cross-sectional structure diagram of a second multi-layer detection structure in an ex-core nuclear detection device provided by an embodiment of the present invention;

[0021] Figure 5 A schematic cross-sectional structure diagram of a third multi-layer detection structure in an out-of-core nuclear detection device provided by an embodiment of the present invention;

[0022] Figure 6 A schematic block diagram of an external core detection system provided by an embodiment of the present invention;

[0023] Figure 7 A method flow chart of a detection data processing method of an ex-core nuclear detection system provided by an embodiment of the present invention;

[0024] Figure 8A sub-flow chart of a detection data processing method of an ex-core nuclear detection system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0027] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0028] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0029] Please also see Figure 1 and Figure 2 ,in Figure 1 A schematic block diagram of an out-of-core nuclear detection device provided by an embodiment of the present invention; Figure 2 The cross-sectional structure diagram of the multi-layer detection structure in the out-of-core nuclear detection device provided by the embodiment of the present invention is shown in FIG. Figure 1 and Figure 2 As shown, the extra-core nuclear detection device 1 disclosed in the embodiment of the present application includes a plurality of source range detector assemblies 10, a plurality of intermediate range detector assemblies 20 and a plurality of power range detector assemblies 30, and the plurality of source range detector assemblies 10, the plurality of intermediate range detector assemblies 20 and the plurality of power range detector assemblies 30 can all be fixed at the boundary of the pressure vessel of the reactor to be detected; the plurality of source range detector assemblies 10, the plurality of intermediate range detector assemblies 20 and the plurality of power range detector assemblies 30 all include a multi-layer detection structure 100; wherein the multi-layer detection structure 100 includes a detector body 110, a moderation material structure 120 and an aluminum shell 130 arranged layer by layer from the inside to the outside.

[0030] In this embodiment, when the plurality of source range detector assemblies 10, the plurality of intermediate range detector assemblies 20 and the plurality of power range detector assemblies 30 all adopt the multi-layer detection structure 100, the moderator material structure 120 is set as a torus structure, the detector body 110 is closely arranged at the center of the torus structure corresponding to the moderator material structure 120, and a layer of aluminum shell 130 is set outside the moderator material structure 120 for fixing and protection, and also to prevent the moderator material from deforming in a high irradiation environment. Specifically, the material used for the moderator material structure 120 is a solid material, such as graphite, polyethylene (PE), polyetheretherketone (PEEK), etc.

[0031] In one embodiment, if Figure 1 and Figure 3 As shown, the multi-layer detection structure included in each of the several source range detector assemblies 10 is recorded as a first multi-layer detection structure 200; the first multi-layer detection structure 200 includes a first detector body 210, a first moderator material structure 220 and a first aluminum shell 230, the first moderator material structure 220 is arranged around the outer wall of the first detector body 210, and the first moderator material structure 220 and the first detector body 210 are both arranged in the inner cavity of the first aluminum shell 230; wherein the material of the first moderator material structure 220 is polyethylene.

[0032] In this embodiment, several source range detector assemblies 10 are mainly used to monitor the neutron flux level at the initial stage of reactor startup, when the neutron flux in the core is relatively low and is at the source level stage. It can detect extremely weak neutron signals, such as the very low neutron flux formed by neutrons from spontaneous fission sources and (α, n) reactions after the first loading of the reactor and before startup, which can help determine the initial neutron-related state of the core. When the multi-layer detection structure included in each of the several source range detector assemblies 10 is recorded as the first multi-layer detection structure 200, the first moderator material structure 220 is set to a torus structure, the first detector body 210 is closely arranged at the center of the torus structure corresponding to the first moderator material structure 220, and a first aluminum shell 230 is set on the outside of the first moderator material structure 220 to play a fixed protection role, and can also prevent the moderator material from deforming in a high irradiation environment. Specifically, the material used for the first annular material structure 220 is polyethylene. Moreover, it has been found through testing that the counting rate of the source range detector assembly with a multi-layer detection structure used in the present application is increased by about 2 to 10 times compared with the reference detector.

[0033] Specifically, before selecting one of the source range detector assemblies 10 to perform a standard source test and a field source test, and selecting one of the intermediate range detector assemblies 20 to perform a standard source test and a field source test, a model of a reactor core physics and a detector output transport calculation model may be built, and the process is as follows:

[0034] A1) constructing a typical detector structure model, for example, constructing a structure model corresponding to a typical detector of a known structure such as a reference detector (such as a reference source range detector component model or a reference intermediate range detector component model);

[0035] A2) Establishing a moderator material database and forming a detector assembly model; for example, moderator material structures corresponding to torus structures of different thicknesses (e.g., a thickness range of 3 to 6 cm) may be constructed, and the moderator material structures of different thicknesses may be respectively set on the outer wall of a typical detector structure model to obtain a plurality of detector assembly models; the typical detector structure model without the moderator material structure set may also be recorded as a reference detector assembly model;

[0036] A3) Establish a core physical model based on the neutron energy group input of the reference reactor core and the core geometry / materials;

[0037] A4) Combining the core physical model and multiple detector component models, a theoretical calculation model for detector count rate is constructed, which can be used to calculate the theoretical values ​​of detector count rate corresponding to multiple detector component models and the reference detector component model.

[0038] It should be noted that the above-mentioned reference detector can be a source range detector or an intermediate range detector. If the reference detector is a source range detector, the constructed detector count rate theoretical calculation model can be used to calculate the detector count rate theoretical values ​​corresponding to multiple source range detector component models and the reference source range detector component model; if the reference detector is an intermediate range detector, the constructed detector count rate theoretical calculation model can be used to calculate the detector count rate theoretical values ​​corresponding to multiple intermediate range detector component models and the reference intermediate range detector component model.

[0039] Specifically, one source range detector assembly can be selected from among several source range detector assemblies 10 to perform a standard source test and a field source test, and one intermediate range detector assembly can be selected from among several intermediate range detector assemblies 20 to perform a standard source test and a field source test. The process is as follows:

[0040] B1) conducting two groups of standard source tests (californium source), simulating the reactor neutron energy spectrum distribution through the neutron source, respectively obtaining a first measured count rate corresponding to a reference source range detector assembly formed by setting a moderator material structure of a torus structure around the outer wall of the reference detector (more specifically, a reference source range detector), and a second measured count rate corresponding to the case where the outer wall of the reference detector is not provided with a moderator material structure; because the previous step A3) can also obtain the detector count rate theoretical value for each detector assembly model provided with a moderator material structure based on the detector count rate theoretical calculation model, at this time, the first measured count rate can also be compared with the first detector count rate theoretical value corresponding to the detector assembly model provided with a moderator material structure of the same thickness, and the second measured count rate can be compared with the reference detector count rate theoretical value corresponding to the reference detector assembly model, and the detector count rate theoretical calculation model is jointly adjusted according to the comparison results of the first measured count rate and the first detector count rate theoretical value and the second measured count rate and the reference detector count rate theoretical value, so as to update the detector count rate theoretical calculation model;

[0041] B2) conducting two groups of standard source tests (californium source), simulating the reactor neutron energy spectrum distribution through the neutron source, respectively obtaining a third measured count rate corresponding to the intermediate range detector assembly (more specifically, the benchmark intermediate range detector) when the moderated material structure has a UHMW-PE (ultra-high molecular weight polyethylene) material, and a fourth measured count rate corresponding to the intermediate range detector assembly when the moderated material structure has a PEEK (polyetheretherketone) material, and evaluating the moderation performance of the benchmark intermediate range detector assembly under the above two different moderator materials through the third measured count rate and the fourth measured count rate;

[0042] B3) 4 groups of on-site source tests (Pu-Be source, i.e., plutonium-beryllium source) were carried out. The first two groups of on-site source tests (Pu-Be source) were conducted by simulating the neutron energy spectrum distribution of a reactor with a neutron source, and the fifth measured count rate corresponding to the reference source range detector assembly formed by setting a moderator material structure with a torus structure around the outer wall of the reference source range detector, and the sixth measured count rate corresponding to the case where the moderator material structure was not set on the outer wall of the reference source range detector was obtained respectively; the last two groups of on-site source tests (Pu-Be source) were conducted by simulating the neutron energy spectrum distribution of a reactor with a neutron source, and the seventh measured count rate corresponding to the source range detector assembly formed by setting a moderator material structure with a torus structure around the outer wall of the source range detector assembly 10, and the eighth measured count rate corresponding to the case where the moderator material structure was not set on the outer wall of the source range detector assembly 10 was obtained respectively. The detection performance difference between the source range detector assembly 10 and the reference source range detector assembly was evaluated by the fifth measured count rate, the sixth measured count rate, the seventh measured count rate, and the eighth measured count rate.

[0043] Among them, it is shown through verification that the seventh measured count rate corresponding to the source range detector assembly formed by the moderator material structure of the torus structure surrounding the outer wall of the source range detector assembly 10, and the eighth measured count rate corresponding to the case where the outer wall of the source range detector assembly 10 is not provided with a moderator material structure, the seventh measured count rate is about 8 times the eighth measured count rate. The third measured count rate corresponding to the intermediate range detector assembly in the case of the moderator material structure of UHMW-PE (ultra-high molecular weight polyethylene) material, and the fourth measured count rate corresponding to the intermediate range detector assembly in the case of the moderator material structure of PEEK (polyetheretherketone) material, the third measured count rate is about 1.9 times the fourth measured count rate. Moreover, the detection performance of the source range detector is about 1.79 times higher than that of the reference source range detector.

[0044] In one embodiment, if Figure 1 and Figure 4 As shown, the multi-layer detection structure included in each of the several intermediate-range detector assemblies 20 is recorded as a second multi-layer detection structure 300; the second multi-layer detection structure 300 includes a second detector body 310, a second moderator material structure 320 and a second aluminum shell 330, the second moderator material structure 320 is arranged around the outer wall of the second detector body 310, and the second moderator material structure 320 and the second detector body 310 are both arranged in the inner cavity of the second aluminum shell 330; wherein the material of the second moderator material structure 320 is polyetheretherketone.

[0045] In this embodiment, the measurement range of several intermediate range detector assemblies 20 is between the source range and the power range, which is mainly used to continuously and accurately track the change of neutron flux when the reactor power begins to leave the extremely low level corresponding to the source range and moves towards a higher power stage corresponding to the power range with a certain power output but not yet reaching the power range. When the multi-layer detection structure included in each of the several intermediate range detector assemblies 20 is recorded as the second multi-layer detection structure 300, the second moderator material structure 320 is set as a torus structure, the second detector body 310 is closely arranged at the center of the torus structure corresponding to the second moderator material structure 320, and a second aluminum shell 330 is set on the outside of the second moderator material structure 320 to play a fixing and protective role, and at the same time, it can also prevent the moderator material from deforming in a high irradiation environment. Specifically, the material used for the second catalytic material structure 320 is polyetheretherketone. Moreover, tests have shown that a second moderator material structure 320 is provided outside the second detector body 310 and is made of polyetheretherketone, which has a high melting point and is suitable for monitoring in high-temperature and high-flux environments, and can meet the requirements of neutron injection rate monitoring in high-temperature and high-irradiation environments under accident conditions.

[0046] In one embodiment, if Figure 1 and Figure 5 As shown, the multi-layer detection structure included in each of the several power range detector assemblies 30 is recorded as a third multi-layer detection structure 400; the third multi-layer detection structure 400 includes a third detector body 410, a third moderator material structure 420 and a third aluminum shell 430, the third moderator material structure 420 is arranged around the outer wall of the third detector body 410, and the third moderator material structure 420 and the third detector body 410 are both arranged in the inner cavity of the third aluminum shell 430; wherein, the material of the third moderator material structure 420 is polyethylene.

[0047] In this embodiment, several power range detector assemblies 30 are mainly used to monitor the neutron flux of the reactor under normal operating power level and high power conditions. When the multi-layer detection structure included in each of the several power range detector assemblies 30 is recorded as the third multi-layer detection structure 400, the third moderator material structure 420 is set as a torus structure, the third detector body 410 is closely arranged at the center of the torus structure corresponding to the third moderator material structure 420, and a third aluminum shell 430 is set outside the third moderator material structure 420 to play a fixing and protective role, and at the same time, it can also prevent the moderator material from deforming under high irradiation environment. Specifically, the material used for the third carbonized material structure 420 is polyethylene.

[0048] In one embodiment, if Figure 1 and Figure 5 As shown, each of the plurality of power range detector assemblies 30 includes 4 to 6 power range detector subassemblies 401 , and each power range detector subassembly 401 includes the multi-layer detection structure 400 .

[0049] In this embodiment, each of the several power range detector assemblies includes 4 to 6 power range detector subassemblies 401, indicating that each power range detector assembly includes 4-6 power range detector subassemblies 401. Moreover, each power range detector subassembly 401 can also adopt a multi-layer detection structure, that is, each power range detector subassembly is provided with a detector body, a moderation material structure and an aluminum shell layer by layer from the inside to the outside. The use of the above-mentioned multi-segment power range detector assembly can more accurately detect the power range of the nuclear power plant's external nuclear power.

[0050] In one embodiment, if Figure 1 - Figure 5 As shown, the thickness of the moderator material structure 120 is 3-6 cm, and the length of the moderator material structure 120 is greater than the length of the detector body 110 .

[0051] In this embodiment, if the moderator material structure 120 is set as a torus structure in specific implementation, the thickness of the moderator material structure 120 can be determined by subtracting the inner diameter of the torus structure from the outer diameter of the torus structure and then dividing it by 2. The use of a moderator material structure 120 of a certain thickness can improve the thermal neutron flux rate at a plurality of source range detector assemblies 10, a plurality of intermediate range detector assemblies 20 or a plurality of power range detector assemblies 30. Since the torus structure corresponding to the moderator material structure 120 is sleeved on the outer wall of the detector body 110, in order to ensure the detection performance, the length of the moderator material structure 120 can be set to be greater than the length of the detector body 110, such as setting the length of the moderator material structure 120 to be slightly greater than the length of the detector body 110 in specific implementation (more specifically, the length difference between the length of the moderator material structure 120 and the length of the detector body 110 is 1 to 5 cm).

[0052] See also Figure 6 , which is a schematic block diagram of an out-of-core nuclear detection system provided by an embodiment of the present invention. Figure 6 As shown, an embodiment of the present application also discloses an extra-core nuclear detection system, including an extra-core nuclear detection device 1 as described in any of the aforementioned embodiments, and also including a penetration piece 2 and a nuclear instrument cabinet 3; wherein the extra-core nuclear detection device 1 is connected to the nuclear instrument cabinet 3 via the penetration piece 2.

[0053] In this embodiment, the detection object of the external core detection system is Figure 6 The reactor core 4 in the reactor, the neutron energy group generated therein will pass through the boundary of the pressure vessel 5 and then be detected by the ex-core nuclear detection device 1, and the detection result of the ex-core nuclear detection device 1 can be transmitted to the nuclear instrument cabinet 3 through the penetration piece 2 for subsequent data processing. Moreover, in order to make the detection result more accurate, multiple source range detector components, multiple intermediate range detector components and several power range detector components can be set in the ex-core nuclear detection device 1, that is, the comprehensive voting result of multiple source range detector components is used as the corresponding detection result, the comprehensive voting result of multiple intermediate range detector components is used as the corresponding detection result, and the comprehensive voting result of multiple power range detector components is used as the corresponding detection result.

[0054] In one embodiment, the ex-core nuclear detection device includes three source range detector assemblies, three intermediate range detector assemblies and four power range detector assemblies.

[0055] Each of the four power range detector assemblies includes 4 to 6 power range detector subassemblies, and each power range detector subassembly includes the multi-layer detection structure.

[0056] The three source range detector components adopt a 2 / 3 voting logic, and the four power range detector components adopt a 2 / 4 voting logic.

[0057] In this embodiment, when three source range detector components, three intermediate range detector components and four power range detector components are provided in the extra-core nuclear detection device, the source range protection function adopts a 2 / 3 voting logic (the 2 / 3 voting logic indicates that three independent related monitoring channels or judgment conditions are involved in the judgment of source range related protection, and when at least two of the monitoring channels or judgment conditions simultaneously meet the specific protection triggering requirements, the corresponding protection action will be initiated), and the power range function adopts a 2 / 4 voting logic (the 2 / 4 voting logic indicates that four independent related monitoring channels or judgment conditions are involved in the judgment of power range related protection, and when at least two of the monitoring channels or judgment conditions simultaneously meet the specific protection triggering requirements, the corresponding protection action will be initiated).

[0058] Specifically, each of the three source range detector components is provided with a power upper limit threshold. For example, the three source range detector components are respectively recorded as the first source range detector component, the second source range detector component and the third source range detector component. When at least two of the detected powers in the first source range detector component to the third source range detector component exceed the corresponding power upper limit threshold, the corresponding source range detector component will send a trigger signal to the nuclear instrument cabinet and the nuclear instrument cabinet will determine that the source range protection conditions are met, and then execute the corresponding protection action to ensure the safe and stable operation of the reactor in the source range stage. Compared with the single-channel detection method, the reliability and accuracy of the entire source range protection are improved.

[0059] Similarly, each of the four power range detector components is provided with a power upper limit threshold. For example, the four power range detector components are respectively recorded as the first power range detector component, the second power range detector component, the third power range detector component and the fourth power range detector component. When at least two of the detected powers of the first power range detector component to the fourth power range detector component exceed the corresponding power upper limit threshold, the corresponding power range detector component will send a trigger signal to the nuclear instrument cabinet and be recognized by the nuclear instrument cabinet as meeting the power range protection conditions, and then start protection measures such as reducing power and switching to backup equipment. Compared with the single-channel detection method, the reliability and accuracy of the entire power range protection are also improved.

[0060] See also Figure 7 , which is a method flow chart of a detection data processing method of an ex-core nuclear detection system provided by an embodiment of the present invention. Figure 7 As shown, the embodiment of the present application also discloses a detection data processing method of an ex-core detection system, which includes the following steps S110 to S140, and the detection data processing method of the ex-core detection system is applied to the ex-core detection system described in any of the above embodiments, and the ex-core detection device described in any of the above embodiments in the ex-core detection system. Figure 1 and Figure 2As shown, the extra-core nuclear detection device 1 includes a plurality of source range detector assemblies 10, a plurality of intermediate range detector assemblies 20 and a plurality of power range detector assemblies 30, and the plurality of source range detector assemblies 10, the plurality of intermediate range detector assemblies 20 and the plurality of power range detector assemblies 30 can all be fixed at the boundary of the pressure vessel of the reactor to be detected; the plurality of source range detector assemblies 10, the plurality of intermediate range detector assemblies 20 and the plurality of power range detector assemblies 30 all include a multi-layer detection structure 100; wherein the multi-layer detection structure 100 includes a detector body 110, a moderation material structure 120 and an aluminum shell 130 arranged layer by layer from the inside to the outside.

[0061] S110, obtaining a first theoretical count rate of the reference detector under the secondary source loading energy spectrum, and obtaining a detection performance ratio of the source range detector and the reference detector in the ex-core nuclear detection system under an on-site plutonium-beryllium source test.

[0062] The source range detector in the ex-core nuclear detection system is a bare structure source range detector after the moderator material structure and the aluminum shell are removed from the source range detector assembly.

[0063] In this embodiment, in order to verify the first theoretical count rate of the source range detector assembly in the ex-core nuclear detection device during secondary source loading, the specific process of the source test is as described in the above steps B1)-B3). Through the above source test, the detection performance ratio of the source range detector and the reference detector in the ex-core nuclear detection system under the on-site plutonium-beryllium source test can also be obtained (such as the ratio between the eighth measured count rate and the sixth measured count rate in the above example as the detection performance ratio). After determining the first theoretical count rate and the detection performance ratio, the second theoretical count rate of the source range detector assembly can be further determined.

[0064] In one embodiment, if Figure 8 As shown, step S110 includes:

[0065] S111, obtaining a current first measured count rate of the reference detector under an on-site plutonium-beryllium source test, and obtaining a first B10 reaction number corresponding to the reference detector, and determining a current detection efficiency according to a ratio of the current first measured count rate to the first B10 reaction number;

[0066] S112, obtaining a second B10 reaction number of the reference detector assembly under the secondary source loading energy spectrum; wherein the reference detector assembly is obtained by arranging a moderator material structure around the outer wall of the reference detector and then arranging an aluminum shell;

[0067] S113. Determine the first theoretical counting rate of the reference detector under the secondary source charging energy spectrum according to the product of the second B10 reaction number and the current detection efficiency.

[0068] In this embodiment, when specifically determining the first theoretical count rate of the reference detector under the secondary source loading energy spectrum, it is first necessary to obtain the current first measured count rate of the reference detector under the on-site plutonium beryllium source test, and obtain the first B10 reaction number corresponding to the reference detector through modeling calculation (the B10 reaction number is the boron 10 reaction number, which refers to the number of nuclear reaction equations involved in boron-10 in nuclear reactions, and boron-10 involves two important nuclear reactions in nuclear reactions, namely, the reaction of boron-10 capturing an alpha particle to generate nitrogen-13, and the reaction of nitrogen-13 decaying to generate carbon-13). Then, the second B10 reaction number of the reference detector under the secondary source loading energy spectrum is obtained, and specifically, the second B10 reaction number of the reference detector assembly under the secondary source loading energy spectrum can be obtained in combination with the aforementioned detector count rate theoretical calculation model. Finally, the product obtained by multiplying the second B10 reaction number and the current detection efficiency is used as the first theoretical count rate of the reference detector under the secondary source loading energy spectrum. It can be seen that through the above method, the first theoretical counting rate of the reference detector under the secondary source loading energy spectrum can be quickly determined by combining the current first measured counting rate of the reference detector under the on-site plutonium-beryllium source test, the first B10 reaction number obtained by the reference detector in the modeling calculation method, and the second B10 reaction number of the reference detector assembly under the secondary source loading energy spectrum.

[0069] In one embodiment, step S110 further includes:

[0070] Obtaining a current third measured count rate of a source range detector in the ex-core nuclear detection system under an on-site plutonium-beryllium source test;

[0071] The detection performance ratio is determined based on a ratio of the current third measured count rate to the current first measured count rate.

[0072] In this embodiment, when obtaining the current third measured count rate of the source range detector in the ex-core nuclear detection system under the on-site plutonium beryllium source test, reference can be made to the process of obtaining the corresponding eighth measured count rate in step B3) when the outer wall of the source range detector assembly 10 is not provided with a moderator material structure. Similarly, when obtaining the current first measured count rate of the reference detector under the on-site plutonium beryllium source test in step S111, reference can be made to the process of obtaining the corresponding sixth measured count rate in step B3) when the outer wall of the reference source range detector is not provided with a moderator material structure. After respectively obtaining the current third measured count rate and the current first measured count rate, the ratio of the current third measured count rate to the current first measured count rate is used as the detection performance ratio. It can be seen that through the above method, the detection performance ratio can be quickly determined by combining the current first measured count rate of the reference detector under the on-site plutonium beryllium source test and the current third measured count rate of the source range detector in the ex-core nuclear detection system under the on-site plutonium beryllium source test.

[0073] S120. Determine a second theoretical count rate of the source range detector assembly according to the first theoretical count rate and the detection performance ratio.

[0074] In this embodiment, after determining the detection performance ratio by the ratio between the eighth measured count rate and the sixth measured count rate in the aforementioned example, the second theoretical count rate of the source range detector assembly can be determined based on a preset operation method. In the above manner, the first theoretical count rate of the reference detector under the secondary source charge energy spectrum and the detection performance ratio of the reference detector are effectively combined to quickly determine the second theoretical count rate of the source range detector assembly.

[0075] In one embodiment, step S120 includes:

[0076] The second theoretical count rate of the source range detector assembly is determined based on a product of the first theoretical count rate and the detection performance ratio.

[0077] In this embodiment, when determining the second theoretical count rate of the source range detector assembly based on a preset operation method, specifically, the product of the first theoretical count rate and the detection performance ratio is obtained, and the product is used as the second theoretical count rate of the source range detector assembly. In the above manner, the second theoretical count rate of the source range detector assembly can be quickly determined by the product of the first theoretical count rate and the detection performance ratio.

[0078] S130, obtaining an estimated probability rate of the source range detector assembly when the neutron source of the reactor to be monitored is in a preset state.

[0079] In this embodiment, the second theoretical count rate of the source range detector assembly has been determined in the previous step. The second theoretical count rate cannot be directly used as the actual application count rate of the source range detector assembly. Further cross-validation is required to obtain a more accurate count rate of the source range detector assembly under the secondary source loading energy spectrum.

[0080] In one embodiment, step S130 includes:

[0081] If it is determined that the preset state corresponding to the neutron source of the reactor to be monitored includes at least one of a plane source state, a body source state and a simulated secondary neutron source state, the estimated probability rates corresponding to the neutron source of the reactor to be monitored under the preset states are obtained.

[0082] Among them, the body source in the body source state is the body source between the source range detector and the guide tube where the neutrons from the reactor are located; the simulated secondary neutron source state is the state where the secondary source neutrons are transported to the source range detector position after subcritical proliferation.

[0083] In this embodiment, the preset states include a plane source state, a body source state and a simulated secondary neutron source state, and the body source in the body source state more specifically refers to the neutrons from the reactor considered as the body source between the detector and the guide tube; the simulated secondary neutron source state more specifically refers to the state of considering the secondary source neutrons, after subcritical proliferation, and transported to the detector position.

[0084] Specifically, the preset state includes a plane source state, a body source state, and a simulated secondary neutron source state, and the estimated count rates corresponding to the above three states are used as verification reference data for the second theoretical count rate. Among them, the three states included in the preset state correspond to an initial estimated count rate respectively, and then the preset conservative estimated count rate is subtracted, or multiplied by the preset conservative estimated ratio, to obtain the estimated count rates corresponding to the three states respectively. Afterwards, the estimated count rates corresponding to the above three states can be used to verify the second theoretical count rate.

[0085] S140. Determine a current calculated count rate of the source range detector assembly based on a comparison result of the second theoretical count rate and the estimated count rate.

[0086] In this embodiment, after determining the estimated count rates corresponding to the neutron sources of the reactor to be monitored under the preset state, the second theoretical count rate can be compared with each estimated count rate, and the final calibration result can be determined in combination with the comparison result and the preset calibration model, and the final calibration result is used as the current calculated count rate of the source range detector assembly. In the above manner, it can be ensured that the current nucleic acid count rate of the source range detector assembly obtained is data with high reliability. The application of the source range detector assembly eliminates the risk of strong unavailability of the secondary source of the first reactor type, and ensures the safe and reliable protection and monitoring of the first reactor loading.

[0087] In one embodiment, step S140 includes:

[0088] The second theoretical counting rate is compared with the estimated counting rates corresponding to the neutron source of the reactor to be monitored under the preset state, and when it is determined that the comparison results between the second theoretical counting rate and the estimated counting rates corresponding to the neutron source of the reactor to be monitored under the preset state both meet the preset calibration model conditions, the second theoretical counting rate is used as the current calculated counting rate corresponding to the source range detector assembly.

[0089] Among them, the verification model condition is that the difference between the second theoretical counting rate and the first estimated counting rate, the second estimated counting rate and the third estimated counting rate corresponding to the neutron source of the reactor to be monitored in the plane source state, the body source state and the simulated secondary neutron source state respectively are all less than the preset verification threshold.

[0090] In this embodiment, specifically, the second theoretical count rate can be compared with the estimated count rates corresponding to the neutron source of the reactor to be monitored under the preset state, for example, the second theoretical count rate can be compared with the estimated count rates corresponding to the above three preset states (i.e., the plane source state, the main source state and the simulated secondary neutron source state). If it is further determined that the comparison results between the second theoretical count rate and the estimated count rates corresponding to the neutron source of the reactor to be monitored under the above three preset states satisfy the preset calibration model conditions (such as when the differences between the second theoretical count rate and the estimated count rates corresponding to the above three preset states are all less than the preset calibration threshold, it can be regarded as satisfying the preset calibration model conditions), then the second theoretical count rate can be directly used as the current calculated count rate corresponding to the source range detector assembly.

[0091] Among them, based on the total injection rate of 8.5n / cm2s at the position of the source range detector component used for loading when the secondary source is out of the pile, the half-life of the secondary source is about 60 days, and the counting rate is about 5.2cps 10 months after leaving the pile; combined with the requirement of a minimum counting rate of 2cps for secondary source loading, the guaranteed secondary source loading time is 300 days.

[0092] In one embodiment, after step S140, the method further includes:

[0093] A corresponding alarm count rate threshold is determined based on the current calculated count rate of the source range detector assembly.

[0094] In this embodiment, the alarm count rate threshold can also be reasonably set to extend the neutron source loading time. Specifically, in combination with the analysis of relevant standards, the minimum count rate monitoring capability achieved by the source range detector assembly has the following conditions: if the alarm count rate threshold is reduced from 2cps to 1cps, the time window for neutron source loading can be extended by about 60 days; if the alarm count rate threshold is reduced from 2cps to 0.5cps, the time window for neutron source loading can be extended by about 120 days. It can be seen that by reducing the signal loss alarm threshold (i.e., the alarm count rate threshold) of the source range detector assembly, the neutron source loading implementation window can be further extended.

[0095] In one embodiment, the determining a corresponding alarm count rate threshold based on the current calculated count rate of the source range detector assembly includes:

[0096] A target preset count rate interval to which the current calculation count rate belongs among multiple preset count rate intervals is obtained, and a target alarm count rate threshold of the target preset count rate interval is used as an alarm count rate threshold corresponding to the current calculation count rate.

[0097] In this embodiment, multiple preset count rate intervals may be pre-set, and an alarm count rate threshold may be set for each preset count rate interval. After obtaining the current calculation count rate, the target preset count rate interval to which the current calculation count rate belongs in the multiple preset count rate intervals may be obtained first, and then the target alarm count rate threshold of the target preset count rate interval may be used as the alarm count rate threshold corresponding to the current calculation count rate. It can be seen that, through the above method, the alarm count rate threshold corresponding to the current calculation count rate may be determined more flexibly and quickly.

[0098] In summary, the embodiments of the present invention provide an ex-core nuclear detection device, a system and a detection data processing method thereof, wherein the ex-core nuclear detection device includes a plurality of source range detector assemblies, a plurality of intermediate range detector assemblies and a plurality of power range detector assemblies, and the plurality of source range detector assemblies, the plurality of intermediate range detector assemblies and the plurality of power range detector assemblies can all be fixed at the boundary of the pressure vessel of the reactor to be detected; the plurality of source range detector assemblies, the plurality of intermediate range detector assemblies and the plurality of power range detector assemblies all include a multi-layer detection structure; wherein the multi-layer detection structure includes a detector body, a moderator material structure and an aluminum shell arranged layer by layer from the inside to the outside. The above-mentioned ex-core nuclear detection device can not only improve the detection sensitivity of various types of detector assemblies by adding a moderator material structure and an aluminum shell to the detector assembly, but also the aluminum shell can prevent the moderator material of the moderator material structure from deforming in a high irradiation environment.

[0099] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. An out-of-core nuclear detection device, characterized in that: It comprises a plurality of source range detector assemblies, a plurality of intermediate range detector assemblies and a plurality of power range detector assemblies, and the plurality of source range detector assemblies, the plurality of intermediate range detector assemblies and the plurality of power range detector assemblies can all be fixed at the boundary of the pressure vessel of the reactor to be detected; the plurality of source range detector assemblies, the plurality of intermediate range detector assemblies and the plurality of power range detector assemblies all comprise a multi-layer detection structure; wherein the multi-layer detection structure comprises a detector body, a moderation material structure and an aluminum shell which are arranged layer by layer from the inside to the outside.

2. The out-of-core nuclear detection device according to claim 1, characterized in that: The multi-layer detection structure included in each of the several source range detector assemblies is recorded as a first multi-layer detection structure; the first multi-layer detection structure includes a first detector body, a first moderator material structure and a first aluminum shell, the first moderator material structure is arranged around the outer wall of the first detector body, and the first moderator material structure and the first detector body are both arranged in the inner cavity of the first aluminum shell; wherein the material of the first moderator material structure is polyethylene.

3. The out-of-core nuclear detection device according to claim 1, characterized in that: The multi-layer detection structure included in each of the several intermediate-range detector assemblies is recorded as a second multi-layer detection structure; the second multi-layer detection structure includes a second detector body, a second moderator material structure and a second aluminum shell, the second moderator material structure is arranged around the outer wall of the second detector body, and the second moderator material structure and the second detector body are both arranged in the inner cavity of the second aluminum shell; wherein, the material of the second moderator material structure is polyetheretherketone.

4. The out-of-core nuclear detection device according to claim 1, characterized in that: The multi-layer detection structure included in each of the several power range detector assemblies is recorded as a third multi-layer detection structure; the third multi-layer detection structure includes a third detector body, a third moderator material structure and a third aluminum shell, the third moderator material structure is arranged around the outer wall of the third detector body, and the third moderator material structure and the third detector body are both arranged in the inner cavity of the third aluminum shell; wherein, the material of the third moderator material structure is polyethylene.

5. The out-of-core nuclear detection device according to claim 4, characterized in that: Each of the plurality of power range detector assemblies includes 4 to 6 power range detector subassemblies, and each power range detector subassembly includes the multi-layer detection structure.

6. The out-of-core nuclear detection device according to any one of claims 1 to 5, characterized in that: The thickness of the moderator material structure is 3-6 cm, and the length of the moderator material structure is greater than the length of the detector body.

7. An out-of-core nuclear detection system, characterized in that: It comprises the out-of-core nuclear detection device as described in any one of claims 1 to 6, and also comprises a penetration piece and a nuclear instrument cabinet; wherein the out-of-core nuclear detection device is connected to the nuclear instrument cabinet through the penetration piece.

8. The out-of-core nuclear detection system according to claim 7, characterized in that: The ex-core nuclear detection device comprises three source range detector assemblies, three intermediate range detector assemblies and four power range detector assemblies.

9. The out-of-core nuclear detection system according to claim 8, characterized in that: Each of the four power range detector assemblies includes 4 to 6 power range detector subassemblies, and each power range detector subassembly includes the multi-layer detection structure.

10. The out-of-core nuclear detection system according to claim 8, characterized in that: The three source range detector components adopt a 2 / 3 voting logic, and the four power range detector components adopt a 2 / 4 voting logic.

11. A detection data processing method for an ex-core nuclear detection system, characterized in that: Applicable to the out-of-core nuclear detection system as described in any one of claims 7 to 10; The detection data processing method of the external nuclear detection system includes: Obtaining a first theoretical count rate of the reference detector under the secondary source loading energy spectrum, and obtaining a detection performance ratio of the source range detector and the reference detector in the ex-core nuclear detection system under an on-site plutonium-beryllium source test; determining a second theoretical count rate of the source range detector assembly based on the first theoretical count rate and the detection performance ratio; Obtaining an estimated probability rate of the source range detector assembly when the neutron source of the reactor to be monitored is in a preset state; Based on the comparison of the second theoretical count rate with the estimated count rate, a currently calculated count rate of the source range detector assembly is determined.

12. The detection data processing method of the out-of-core nuclear detection system according to claim 11, characterized in that: The step of obtaining a first theoretical count rate of the reference detector under the secondary source loading energy spectrum comprises: Obtaining a current first measured count rate of the reference detector under an on-site plutonium-beryllium source test, and obtaining a first B10 reaction number corresponding to the reference detector, and determining a current detection efficiency according to a ratio of the current first measured count rate to the first B10 reaction number; Obtaining a second B10 reaction number of the reference detector assembly under the secondary source loading energy spectrum; wherein the reference detector assembly is obtained by arranging a moderator material structure around the outer wall of the reference detector and then arranging an aluminum shell; The first theoretical counting rate of the reference detector under the secondary source charging energy spectrum is determined according to the product of the second B10 reaction number and the current detection efficiency.

13. The detection data processing method of the out-of-core nuclear detection system according to claim 11, characterized in that: The determining a second theoretical count rate of the source range detector assembly according to the first theoretical count rate and the detection performance ratio comprises: The second theoretical count rate of the source range detector assembly is determined based on a product of the first theoretical count rate and the detection performance ratio.

14. The method for processing output detection data of an out-of-core nuclear detection system according to claim 11, characterized in that: The obtaining of the estimated probability rate of the source range detector assembly when the neutron source of the reactor to be monitored is in a preset state includes: If it is determined that the preset state corresponding to the neutron source of the reactor to be monitored includes at least one of a plane source state, a body source state and a simulated secondary neutron source state, the estimated probability rates corresponding to the neutron source of the reactor to be monitored under the preset states are obtained.

15. The detection data processing method of the out-of-core nuclear detection system according to claim 14, characterized in that: The step of determining a current calculated count rate of the source range detector assembly based on a comparison result of the second theoretical count rate and the estimated count rate comprises: The second theoretical counting rate is compared with the estimated counting rates corresponding to the neutron source of the reactor to be monitored under the preset state, and when it is determined that the comparison results between the second theoretical counting rate and the estimated counting rates corresponding to the neutron source of the reactor to be monitored under the preset state both meet the preset calibration model conditions, the second theoretical counting rate is used as the current calculated counting rate corresponding to the source range detector assembly.

16. The detection data processing method of the out-of-core nuclear detection system according to claim 14, characterized in that: After the step of determining a current calculated count rate of the source range detector assembly based on the comparison result of the second theoretical count rate with the estimated count rate, the method further comprises: A corresponding alarm count rate threshold is determined based on the current calculated count rate of the source range detector assembly.

17. The detection data processing method of the out-of-core nuclear detection system according to claim 16, characterized in that: The determining a corresponding alarm count rate threshold based on the current calculated count rate of the source range detector assembly includes: A target preset count rate interval to which the current calculation count rate belongs among multiple preset count rate intervals is obtained, and a target alarm count rate threshold of the target preset count rate interval is used as an alarm count rate threshold corresponding to the current calculation count rate.

18. The detection data processing method of the out-of-core nuclear detection system according to claim 12, characterized in that: The step of obtaining the detection performance ratio of the source range detector and the reference detector in the ex-core nuclear detection system under the on-site plutonium-beryllium source test comprises: Obtaining a current third measured count rate of a source range detector in the ex-core nuclear detection system under an on-site plutonium-beryllium source test; The detection performance ratio is determined based on a ratio of the current third measured count rate to the current first measured count rate.

19. The detection data processing method of the out-of-core nuclear detection system according to claim 15, characterized in that: The verification model condition is that the differences between the second theoretical counting rate and the first estimated counting rate, the second estimated counting rate and the third estimated counting rate corresponding to the neutron source of the reactor to be monitored in the plane source state, the body source state and the simulated secondary neutron source state are all less than the preset verification threshold.

20. The detection data processing method of the out-of-core nuclear detection system according to claim 14, characterized in that: The body source in the body source state is the body source between the source range detector and the guide tube where the neutrons from the reactor are located; the simulated secondary neutron source state is the state where the secondary source neutrons are transported to the source range detector position after subcritical proliferation.

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