Excore nuclear probe device, system and its probe data processing method

Abstract

The application discloses an out-of-pile nuclear detection device, a system and a detection data processing method thereof, the out-of-pile nuclear detection device 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 assemblies can be fixed at the boundary of the pressure vessel of the reactor to be detected; the source range detector assemblies, the intermediate range detector assemblies and the power range detector assemblies all comprise a multilayer detection structure; wherein the multilayer detection structure comprises a detector body, a moderator material structure and an aluminum shell arranged layer by layer from inside to outside. The out-of-pile nuclear detection device can improve the detection sensitivity of each type of detector assembly by additionally arranging the moderator material structure and the aluminum shell on the detector assembly, and the aluminum shell can prevent the deformation of the moderator material structure of the moderator material in a high radiation environment.

Description

Technical Field

[0001] This invention relates to the field of nuclear measurement components in nuclear instrumentation systems, and more particularly to off-core nuclear detection devices, systems, and methods for processing detection data. Background Technology

[0002] The external nuclear detection system (RPN, also known as the nuclear instrumentation system) characterizes the nuclear power of the reactor core fuel by measuring the neutron reaction in the reactor core through a series of neutron detector assemblies placed around the reactor pressure vessel. During the initial fuel loading of a nuclear power plant unit, a neutron source (a device that releases neutrons) is needed to activate the new fuel in order to meet the minimum neutron flux monitoring requirements specified by standards. Commercial reactor neutron sources include primary neutron sources (typically Cf252) and secondary neutron sources (typically Sb-Be). Primary neutron sources have long half-lives and high intensity, but are expensive; secondary neutron sources are baked into the core of an existing unit during operation, and are relatively inexpensive, but have short half-lives and rapid intensity decay.

[0003] Currently, some reactor types use secondary neutron sources for reactor fuel loading. Secondary neutron sources decay faster and have a shorter effective loading time than primary neutron sources. In order to ensure that the secondary neutron source can be used for loading for as long as possible, the detection performance of the external nuclear detection detector assembly is required.

[0004] The existing RPN system design and core of the CPR1000 reactor are relatively mature and stable. The RPN system detectors use a modular design, and the bare detectors in the existing reactor types have low sensitivity. Without performance improvements, they cannot meet the sensitivity requirements of secondary source loading in the new reactor types. More specifically, the existing RPN system has the following technical shortcomings:

[0005] 1) Due to the lack of systematic modeling and analysis, the source range detector has low sensitivity and cannot be applied to the monitoring of new stack loading.

[0006] 2) The intermediate range is a compensated ionization chamber scheme, which does not meet the long-term monitoring requirements after an accident according to RG1.97; where RG1.97 refers to RG1.97 "Guidelines for Instrumentation of Accident Monitoring in Nuclear Power Plants". Summary of the Invention

[0007] The present invention provides an off-core nuclear detection device, system and detection data processing method, which aims to solve the problem that the source range detector in the existing nuclear instrumentation system has low sensitivity, which makes it impossible to apply to the fuel loading monitoring of new reactor types.

[0008] In a first aspect, embodiments of the present invention provide 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, wherein 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 pressure vessel boundary 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.

[0009] Secondly, embodiments of this application also provide an off-pile nuclear detection system, which includes the off-pile nuclear detection device as described in the first aspect above, and further includes a penetrating member and a nuclear instrument cabinet; wherein the off-pile nuclear detection device is connected to the nuclear instrument cabinet through the penetrating member.

[0010] Thirdly, embodiments of this application also provide a method for processing detection data of an external nuclear detection system, which is applied to the external nuclear detection system described in the second aspect above; the method for processing detection data of the external nuclear detection system includes:

[0011] Obtain the first theoretical count rate of the reference detector under the secondary source charge energy spectrum, and obtain the detection performance ratio of the source range detector assembly and the reference detector in the extra-core nuclear detection system under the field plutonium-beryllium source test.

[0012] The second theoretical count rate of the source range detector assembly is determined based on the ratio of the first theoretical count rate to the detection performance.

[0013] The source range detector assembly is used to obtain a pre-estimated number rate when the neutron source of the reactor under test is in a preset state.

[0014] Based on the comparison between the second theoretical count rate and the estimated count rate, the current calculated count rate of the source range detector assembly is determined.

[0015] This invention provides an extra-reactor nuclear detection device, system, and detection data processing method. The extra-reactor nuclear detection device includes several source-range detector assemblies, several intermediate-range detector assemblies, and several power-range detector assemblies, all of which can be fixed at the pressure vessel boundary of the reactor to be detected. Each of the source-range, intermediate-range, and power-range detector assemblies includes a multi-layer detection structure. The multi-layer detection structure includes a detector body, a moderator material structure, and an aluminum shell, arranged layer by layer from the inside out. This extra-reactor nuclear detection device not only improves the detection sensitivity of various types of detector assemblies by adding a moderator material structure and an aluminum shell to the detector assemblies, but the aluminum shell also prevents deformation of the moderator material structure under high radiation environments. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic block diagram of an off-pile nuclear detection device provided in an embodiment of the present invention;

[0018] Figure 2 This is a cross-sectional schematic diagram of the multi-layer detection structure in the extra-core nuclear detection device provided in an embodiment of the present invention;

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

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

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

[0022] Figure 6 This is a schematic block diagram of an off-pile nuclear detection system provided in an embodiment of the present invention;

[0023] Figure 7 This is a flowchart of a method for processing detection data from an off-core nuclear detection system provided in an embodiment of the present invention.

[0024] Figure 8This is a sub-flowchart of the detection data processing method for the off-core nuclear detection system provided in an embodiment of the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort 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 “comprising” and “including” indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

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

[0028] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0029] Please also refer to Figure 1 and Figure 2 ,in Figure 1 This is a schematic block diagram of an off-pile nuclear detection device provided in an embodiment of the present invention; Figure 2 This is a cross-sectional schematic diagram of the multi-layer detection structure in the extra-core nuclear detection device provided in an embodiment of the present invention. Figure 1 and Figure 2 As shown, the off-pile nuclear detection device 1 disclosed in this 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. 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 pressure vessel boundary 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. The multi-layer detection structure 100 includes a detector body 110, a moderator 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 components 10, the plurality of intermediate range detector components 20, and the plurality of power range detector components 30 all adopt a multi-layer detection structure 100, the moderating material structure 120 is set as a ring structure, and the detector body 110 is closely arranged at the center of the corresponding ring structure of the moderating material structure 120. An aluminum shell 130 is provided on the outside of the moderating material structure 120 for fixation and protection, and also to prevent deformation of the moderating material under high radiation conditions. Specifically, the moderating material structure 120 is made of a solid material, such as graphite, polyethylene (PE), or polyetheretherketone (PEEK).

[0031] In one embodiment, such as Figure 1 and Figure 3 As shown, each of the plurality of source range detector assemblies 10 includes a multi-layer detection structure, referred to as the 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 disposed around the outer wall of the first detector body 210, and both the first moderator material structure 220 and the first detector body 210 are disposed within the inner cavity of the first aluminum shell 230. The first moderator material structure 220 is made of polyethylene.

[0032] In this embodiment, several source range detector assemblies 10 are mainly used to monitor the neutron flux level during the initial stage of reactor startup, when the neutron flux in the core is relatively low, at the source level stage. It can detect extremely weak neutron signals, such as the very low neutron flux generated by spontaneous fission sources and (α, n) reactions after the initial fuel loading and before startup, which helps 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 denoted as the first multi-layer detection structure 200, the first moderator material structure 220 is set as a ring structure, the first detector body 210 is tightly arranged at the center of the ring structure corresponding to the first moderator material structure 220, and a first aluminum outer shell 230 is provided on the outside of the first moderator material structure 220 for fixation and protection, while also preventing deformation of the moderator material under high radiation conditions. Specifically, the material used for the first ring structure 220 is polyethylene. Moreover, tests have shown that the source range detector assembly with a multi-layer detection structure used in this application increases the count rate by about 2 to 10 times compared to the reference detector.

[0033] Specifically, before selecting one source range detector assembly 10 from several source range detector assemblies 10 for standard source tests and field source tests, and before selecting one intermediate range detector assembly 20 from several intermediate range detector assemblies 20 for standard source tests and field source tests, a modeling process for the core physics and detector output transport calculation model of a certain reactor type can be performed. The process is as follows:

[0034] A1) Construct typical detector structure models, such as constructing the structure model corresponding to a typical detector with a known structure (e.g., a reference source range detector component model or a reference intermediate range detector component model).

[0035] A2) Establish a moderating material database and form detector component models; for example, moderating material structures corresponding to toroidal structures of different thicknesses (such as thickness range of 3 to 6 cm) can be constructed, and moderating material structures of different thicknesses can be fitted onto the outer wall of a typical detector structure model to obtain multiple detector component models; or a typical detector structure model without moderating material structures can be recorded as a reference detector component model.

[0036] A3) By comprehensively referencing the neutron energy group input of the reactor core and combining it with the core geometry / materials, a core physics model is established;

[0037] A4) Combining the core physics 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 benchmark detector component model respectively.

[0038] It is important to note that the aforementioned reference detector can be either a source-range detector or an intermediate-range detector. If the reference detector is a source-range detector, the resulting theoretical detector count rate calculation model can be used to calculate the theoretical detector count rate values ​​corresponding to multiple source-range detector component models and the reference source-range detector component model, respectively. If the reference detector is an intermediate-range detector, the resulting theoretical detector count rate calculation model can be used to calculate the theoretical detector count rate values ​​corresponding to multiple intermediate-range detector component models and the reference intermediate-range detector component model, respectively.

[0039] Specifically, one source range detector assembly 10 can be selected from several source range detector assemblies 10 for standard source testing and field source testing. Similarly, one intermediate range detector assembly 20 can be selected from several intermediate range detector assemblies 20 for standard source testing and field source testing. The process is as follows:

[0040] B1) Conduct two sets of standard source experiments (californium source). By simulating the neutron energy spectrum distribution of the neutron source reactor, obtain the first measured count rate corresponding to the reference source range detector assembly formed by surrounding the outer wall of the reference detector (more specifically, the reference source range detector) with a toroidal moderated material structure, and the second measured count rate corresponding to the outer wall of the reference detector without a moderated material structure. Since the previous step A3) can also obtain the theoretical value of the detector count rate for each detector assembly model with a moderated material structure based on the detector count rate theoretical calculation model, the first measured count rate can be compared with the theoretical value of the first detector count rate corresponding to the detector assembly model with a moderated material structure of the same thickness. At the same time, the second measured count rate can be compared with the theoretical value of the reference detector count rate corresponding to the reference detector assembly model. Based on the comparison results of the first measured count rate with the first detector count rate theoretical value and the second measured count rate with the reference detector count rate theoretical value, the detector count rate theoretical calculation model can be adjusted together to update the detector count rate theoretical calculation model.

[0041] B2) Two sets of standard source experiments (californium source) were conducted. By simulating the neutron energy spectrum distribution of the neutron source reactor, the third measured count rate of the intermediate range detector assembly (more specifically, the reference intermediate range detector) with a UHMW-PE (ultra-high molecular weight polyethylene) moderating material structure and the fourth measured count rate of the intermediate range detector assembly with a PEEK (polyether ether ketone) moderating material structure were obtained. The moderating performance of the reference intermediate range detector assembly under the above two different moderating materials was evaluated by the third and fourth measured count rates.

[0042] B3) Four sets of field source experiments (Pu-Be sources, i.e., plutonium-beryllium sources) were conducted. The first two sets of field source experiments (Pu-Be sources) simulated the neutron energy spectrum distribution of a neutron source reactor and obtained the fifth measured count rate corresponding to the reference source range detector assembly with a toroidal moderator structure surrounding the outer wall of the reference source range detector, and the sixth measured count rate corresponding to the reference source range detector assembly without a moderator structure on the outer wall. The latter two sets of field source experiments (Pu-Be sources) simulated the neutron energy spectrum distribution of a neutron source reactor and obtained the seventh measured count rate corresponding to the source range detector assembly 10 with a toroidal moderator structure surrounding the outer wall of the source range detector assembly 10, and the eighth measured count rate corresponding to the source range detector assembly 10 without a moderator structure on the outer wall. The difference in detection performance between the source range detector assembly 10 and the reference source range detector assembly was evaluated by using the fifth, sixth, seventh, and eighth measured count rates.

[0043] Verification showed that, for the source range detector assembly 10 with a ring-shaped moderating material structure surrounding its outer wall, the seventh measured count rate is approximately eight times higher than the eighth measured count rate when the outer wall of the source range detector assembly 10 is not equipped with a moderating material structure. For the intermediate range detector assembly with a UHMW-PE (ultra-high molecular weight polyethylene) moderating material structure, the third measured count rate is approximately 1.9 times higher than the fourth measured count rate when the intermediate range detector assembly has a PEEK (polyether ether ketone) moderating material structure. Furthermore, the detection performance of the source range detector is approximately 1.79 times higher than that of the reference source range detector.

[0044] In one embodiment, such as Figure 1 and Figure 4 As shown, each of the plurality of intermediate range detector assemblies 20 includes a multi-layer detection structure, referred to as a second multi-layer detection structure 300. The second multi-layer detection structure 300 includes a second detector body 310, a second moderating material structure 320, and a second aluminum shell 330. The second moderating material structure 320 is disposed around the outer wall of the second detector body 310, and both the second moderating material structure 320 and the second detector body 310 are disposed within the inner cavity of the second aluminum shell 330. The material of the second moderating material structure 320 is polyetheretherketone (PEEK).

[0045] In this embodiment, the measurement range of several intermediate-range detector components 20 lies between the source range and the power range. They are primarily used to continuously and accurately track changes in neutron flux as the reactor power begins to deviate from the extremely low level corresponding to the source range and moves towards a higher power stage with a certain power output, but not yet reaching the power range. When the multi-layered detection structure included in each of the intermediate-range detector components 20 is designated as the second multi-layered detection structure 300, the second moderator material structure 320 is configured as a ring structure. The second detector body 310 is tightly arranged at the center of the ring structure corresponding to the second moderator material structure 320. A second aluminum outer shell 330 is provided on the outside of the second moderator material structure 320 for fixation and protection, while also preventing deformation of the moderator material under high irradiation conditions. Specifically, the material used for the second catalyst material structure 320 is polyetheretherketone (PEEK). Moreover, tests have shown that the second moderation material structure 320, made of polyetheretherketone (PEEK), is installed outside the second detector body 310. It has a high melting point and is suitable for monitoring in high-temperature and high-flux environments, which can meet the requirements for neutron flux rate monitoring in high-temperature and high-irradiation environments under accident conditions.

[0046] In one embodiment, such as Figure 1 and Figure 5 As shown, each of the plurality of power range detector assemblies 30 includes a multi-layer detection structure, referred to as the 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 disposed around the outer wall of the third detector body 410, and both the third moderator material structure 420 and the third detector body 410 are disposed within 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 levels and high power conditions. When the multi-layer detection structure included in each of the power range detector assemblies 30 is designated as the third multi-layer detection structure 400, the third moderator material structure 420 is configured as a ring structure. The third detector body 410 is tightly arranged at the center of the corresponding ring structure of the third moderator material structure 420, and a third aluminum outer shell 430 is provided on the outside of the third moderator material structure 420 for fixation and protection, while also preventing deformation of the moderator material under high radiation conditions. Specifically, the material used for the third carbide material structure 420 is polyethylene.

[0048] In one embodiment, such as 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 multilayer detection structure 400.

[0049] In this embodiment, each of the plurality of power range detector assemblies includes 4 to 6 power range detector subassemblies 401, meaning that each power range detector assembly includes 4-6 power range detector subassemblies 401. Furthermore, each power range detector subassembly 401 can also employ a multi-layer detection structure, that is, each power range detector subassembly consists of a detector body, a moderator material structure, and an aluminum shell arranged layer by layer from the inside out. Using the above-mentioned multi-segment power range detector assembly enables more accurate detection of the power range of nuclear power outside the nuclear reactor of a nuclear power plant.

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

[0051] In this embodiment, if the moderating material structure 120 is configured as a ring structure, its thickness is determined by subtracting the inner diameter of the ring structure from its outer diameter and then dividing by 2. Using a moderating material structure 120 of a certain thickness can improve the thermal neutron fluence at several source range detector assemblies 10, several intermediate range detector assemblies 20, or several power range detector assemblies 30. Since the ring structure corresponding to the moderating material structure 120 is fitted onto the outer wall of the detector body 110, the length of the moderating material structure 120 can be set to be greater than the length of the detector body 110 to ensure detection performance. For example, in a specific implementation, the length of the moderating material structure 120 can be set to be slightly greater than the length of the detector body 110 (more specifically, the length difference between the length of the moderating material structure 120 and the length of the detector body 110 is 1–5 cm).

[0052] Please see Figure 6 This is a schematic block diagram of the off-core nuclear detection system provided in an embodiment of the present invention. Figure 6 As shown in the figure, this application also discloses an off-pile nuclear detection system, including an off-pile nuclear detection device 1 as described in any of the foregoing embodiments, and further including a penetrating member 2 and a nuclear instrument cabinet 3; wherein, the off-pile nuclear detection device 1 is connected to the nuclear instrument cabinet 3 through the penetrating member 2.

[0053] In this embodiment, the target of the extra-core nuclear detection system is Figure 6 In the reactor core 4, the generated neutron energy clusters pass through the boundary of the pressure vessel 5 and are detected by the external nuclear detection device 1. The detection results of the external nuclear detection device 1 are transmitted to the nuclear instrument cabinet 3 through the penetrating component 2 for subsequent data processing. Moreover, to make the detection results more accurate, multiple source range detector assemblies, multiple intermediate range detector assemblies, and several power range detector assemblies can be set in the external nuclear detection device 1. That is, the combined voting results of multiple source range detector assemblies, the combined voting results of multiple intermediate range detector assemblies, and the combined voting results of multiple power range detector assemblies are used as the corresponding detection results.

[0054] In one embodiment, the off-pile 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 four to six power range detector subassemblies, and each power range detector subassembly includes the multi-layer detection structure.

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

[0057] In this embodiment, when the off-pile nuclear detection device is equipped with 3 source range detector components, 3 intermediate range detector components, and 4 power range detector components, the source range protection function adopts a 2 / 3 voting logic (the 2 / 3 voting logic means that there are 3 independent related monitoring channels or judgment conditions involved in the judgment involving source range related protection, and when at least 2 of the monitoring channels or judgment conditions simultaneously meet the specific protection triggering requirements, the corresponding protection action will be activated), and the power range function adopts a 2 / 4 voting logic (the 2 / 4 voting logic means that there are 4 independent related monitoring channels or judgment conditions involved in the judgment involving power range related protection, and when at least 2 of the monitoring channels or judgment conditions simultaneously meet the specific protection triggering requirements, the corresponding protection action will be activated).

[0058] Specifically, each of the three source range detector assemblies is configured with a power upper limit threshold. For example, these three source range detector assemblies can be designated as the first, second, and third source range detector assemblies. When at least two of the first to third source range detector assemblies detect power exceeding their respective power upper limit thresholds, the corresponding source range detector assembly will send a trigger signal to the nuclear instrument cabinet. The nuclear instrument cabinet will then recognize that the conditions for source range protection have been met and execute the corresponding protection action to ensure the safe and stable operation of the reactor during the source range phase. Compared to single-channel detection methods, this improves the reliability and accuracy of the overall source range protection.

[0059] Similarly, each of the four power range detector components is configured with a power upper limit threshold. For example, these four power range detector components can be designated as the first, second, third, and fourth power range detector components. When at least two of the first to fourth power range detector components detect power exceeding their corresponding power upper limit thresholds, the corresponding power range detector component will send a trigger signal to the nuclear instrument cabinet. The nuclear instrument cabinet will then recognize that the power range protection conditions have been met and initiate protective measures such as power reduction or switching to backup equipment. Compared to single-channel detection, this also improves the reliability and accuracy of the overall power range protection.

[0060] Please see Figure 7 This is a flowchart of the detection data processing method for the extra-core nuclear detection system provided in this embodiment of the invention. Figure 7 As shown, this application also discloses a detection data processing method for an external nuclear detection system, which includes the following steps S110 to S140, and the detection data processing method for the external nuclear detection system is applied to the external nuclear detection system described in any of the foregoing embodiments, wherein the external nuclear detection device described in any of the foregoing embodiments is located in the external nuclear detection system. Furthermore, as... Figure 1 and Figure 2As shown, the extra-core nuclear detection device 1 includes several source range detector assemblies 10, several intermediate range detector assemblies 20, and several power range detector assemblies 30. Each of these components can be fixed at the pressure vessel boundary of the reactor to be detected. Each of these components includes a multi-layer detection structure 100. The multi-layer detection structure 100 includes a detector body 110, a moderator material structure 120, and an aluminum outer shell 130 arranged layer by layer from the inside out.

[0061] S110. Obtain the first theoretical count rate of the reference detector under the secondary source charge energy spectrum, and obtain the detection performance ratio of the source range detector and the reference detector in the off-core nuclear detection system under the field plutonium-beryllium source test.

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

[0063] In this embodiment, to verify the first theoretical count rate of the source range detector assembly in the off-pile nuclear detection device during secondary source loading, the specific process of the source test is as described in steps B1)-B3) above. Through the aforementioned source test, the detection performance ratio of the source range detector and the reference detector in the off-pile nuclear detection system under on-site plutonium-beryllium source testing can also be obtained (e.g., the ratio between the eighth and sixth measured count rates in the aforementioned example is used 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, such as Figure 8 As shown, step S110 includes:

[0065] S111. Obtain the current first measured count rate of the reference detector under the on-site plutonium-beryllium source test, and obtain the first B10 response number corresponding to the reference detector. Determine the current detection efficiency based on the ratio of the current first measured count rate to the first B10 response number.

[0066] S112. Obtain the second B10 reaction number of the reference detector assembly under the secondary source charge energy spectrum; wherein, the reference detector assembly is obtained by setting a moderation material structure around the outer wall of the reference detector and then setting an aluminum shell;

[0067] S113. Determine the first theoretical count rate of the reference detector under the secondary source charge energy spectrum based on the product of the second B10 reaction number and the current detection efficiency.

[0068] In this embodiment, when determining the first theoretical count rate of the reference detector under the secondary source charge 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 experiment, and then 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 the boron-10 nuclear reaction, and the two important nuclear reactions involved in the boron-10 nuclear reaction are the reaction in which boron-10 captures an alpha particle to generate nitrogen-13, and the reaction in which nitrogen-13 decays to generate carbon-13). Then, the second B10 reaction number of the reference detector under the secondary source charge energy spectrum is obtained, specifically by combining the aforementioned detector count rate theoretical calculation model to obtain the second B10 reaction number of the reference detector component under the secondary source charge energy spectrum. Finally, the product obtained by multiplying the second B10 reaction number by the current detection efficiency is taken as the first theoretical count rate of the reference detector under the secondary source charge energy spectrum. As can be seen, by combining the first measured count rate of the reference detector under the 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 charge energy spectrum, the first theoretical count rate of the reference detector under the secondary source charge energy spectrum can be quickly determined.

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

[0070] Obtain the current third measured count rate of the source range detector in the off-pile nuclear detection system under the on-site plutonium-beryllium source test;

[0071] The detection performance ratio is determined based on the 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 off-pile nuclear detection system under the on-site plutonium-beryllium source test, the process of obtaining the eighth measured count rate corresponding to the case where the outer wall of the source range detector assembly 10 is not equipped with a moderator material structure can be referred to in step B3). Similarly, when obtaining the current first measured count rate of the reference detector under the on-site plutonium-beryllium source test in step S111, the process of obtaining the sixth measured count rate corresponding to the case where the outer wall of the reference source range detector is not equipped with a moderator material structure can be referred to in step B3). After obtaining the current third measured count rate and the current first measured count rate respectively, 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 off-pile nuclear detection system under the on-site plutonium-beryllium source test.

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

[0074] In this embodiment, after determining the detection performance ratio by the ratio between the eighth and sixth measured count rates in the aforementioned example, the second theoretical count rate of the source range detector assembly can be determined based on a preset calculation method. This method effectively combines the first theoretical count rate of the reference detector under the secondary source charge energy spectrum with the detection performance ratio of the reference detector, quickly determining 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 the 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 calculation method, specifically, the product of the first theoretical count rate and the detection performance ratio is obtained, and this product is used as the second theoretical count rate of the source range detector assembly. Through this method, the second theoretical count rate of the source range detector assembly can be quickly determined from the product of the first theoretical count rate and the detection performance ratio.

[0078] S130. Obtain the estimated number 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 steps. However, this 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 charge energy spectrum.

[0080] In one embodiment, step S130 includes:

[0081] If the preset state corresponding to the neutron source of the reactor under monitoring is determined to include at least one of the planar source state, the bulk source state, and the simulated secondary neutron source state, then the estimated number rate corresponding to the neutron source of the reactor under monitoring in the preset state is obtained respectively.

[0082] In the above-mentioned source state, the source is the neutron source from the reactor between the source range detector and the guide tube; the simulated secondary neutron source state is the state in which secondary source neutrons are transported to the source range detector position after subcritical multiplication.

[0083] In this embodiment, the preset state includes a planar source state, a bulk source state, and a simulated secondary neutron source state. Specifically, the bulk source state refers to neutrons from the reactor being considered as a bulk source between the detector and the guide tube. The simulated secondary neutron source state refers to a state in which secondary source neutrons are considered to be multiplied by subcriticality and then transported to the detector position.

[0084] Specifically, the preset states include a planar source state, a bulk source state, and a simulated secondary neutron source state. The estimated count rates corresponding to these three states are used as verification reference data for the second theoretical count rate. Each of the three preset states corresponds to an initial estimated count rate. Subtracting a preset conservative estimated count rate, or multiplying by a preset conservative estimated ratio, yields the estimated count rates corresponding to each of the three states. These estimated count rates can then be used to verify the second theoretical count rate.

[0085] S140. Based on the comparison result between the second theoretical count rate and the estimated count rate, determine the current calculated count rate of the source range detector component.

[0086] In this embodiment, after determining the estimated count rates corresponding to the neutron sources of the reactor under the preset conditions, the second theoretical count rate can be compared with each estimated count rate. The final calibration result is determined by combining the comparison results with a preset calibration model, and this final calibration result is used as the current calculated count rate of the source range detector component. This method ensures that the current nucleic acid count rate of the source range detector component is highly reliable data. The application of this source range detector component eliminates the risk of unavailability of the secondary source strength in the first reactor, ensuring safe and reliable protection and monitoring of the first reactor's fuel loading.

[0087] In one embodiment, step S140 includes:

[0088] The second theoretical count rate is compared with the estimated count rate corresponding to the neutron source of the reactor under the preset state. If the comparison results between the second theoretical count rate and the estimated count rate corresponding to the neutron source of the reactor under the preset state both satisfy the preset verification model conditions, then the second theoretical count rate is used as the current calculated count rate corresponding to the source range detector component.

[0089] The verification model condition is that the difference between the second theoretical count rate and the first, second, and third estimated count rates of the neutron source of the reactor to be monitored in the planar source state, the bulk source state, and the simulated secondary neutron source state, respectively, is less than a preset verification threshold.

[0090] In this embodiment, the second theoretical count rate can be compared with the estimated count rate corresponding to the neutron source of the reactor under the preset state. For example, the second theoretical count rate can be compared with the estimated count rate corresponding to the three preset states (i.e., planar source state, main source state, and simulated secondary neutron source state). If it is further determined that the comparison results between the second theoretical count rate and the estimated count rate corresponding to the neutron source of the reactor under the preset state all meet the preset verification model conditions (e.g., when the difference between the second theoretical count rate and the estimated count rate corresponding to the three preset states is less than the preset verification threshold, it can be regarded as meeting the preset verification model conditions), then the second theoretical count rate can be directly used as the current calculated count rate corresponding to the source range detector component.

[0091] Based on the calculation of the total flux rate of the position of the secondary source range detector component used for charging at the time of secondary source discharge, which is 8.5 n / cm2s, the half-life of the secondary source is about 60 days, and the count rate is about 5.2 cps 10 months after discharge; combined with the requirement of a minimum count rate of 2 cps for secondary source charging, the secondary source charging time can be guaranteed for 300 days.

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

[0093] The corresponding alarm count rate threshold is determined based on the current count rate of the source range detector component.

[0094] In this embodiment, the alarm count rate threshold can be reasonably set to extend the neutron source loading time. Specifically, based on relevant standards, the minimum count rate monitoring capability achieved by the source range detector component has the following limitations: reducing the alarm count rate threshold from 2 cps to 1 cps can extend the neutron source loading time window by approximately 60 days; reducing the alarm count rate threshold from 2 cps to 0.5 cps can extend the neutron source loading time window by approximately 120 days. Therefore, by reducing the signal loss alarm threshold (i.e., the alarm count rate threshold) of the source range detector component, the neutron source loading implementation window can be further extended.

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

[0096] Obtain the target preset count rate interval to which the current calculated count rate belongs among multiple preset count rate intervals, and use the target alarm count rate threshold of the target preset count rate interval as the alarm count rate threshold corresponding to the current calculated count rate.

[0097] In this embodiment, multiple preset count rate intervals can be pre-set, and an alarm count rate threshold can be set for each preset count rate interval. After obtaining the current calculated count rate, the target preset count rate interval to which the current calculated count rate belongs among the multiple preset count rate intervals can be obtained first. Then, the target alarm count rate threshold of the target preset count rate interval can be used as the alarm count rate threshold corresponding to the current calculated count rate. It is evident that the above method allows for a more flexible and rapid determination of the alarm count rate threshold corresponding to the current calculated count rate.

[0098] In summary, the embodiments of the present invention provide an extra-reactor nuclear detection device, system, and detection data processing method thereof. The extra-reactor nuclear detection device includes several source-range detector assemblies, several intermediate-range detector assemblies, and several power-range detector assemblies, all of which can be fixed at the pressure vessel boundary of the reactor to be detected. Each of the source-range, intermediate-range, and power-range detector assemblies includes a multi-layer detection structure. The multi-layer detection structure includes a detector body, a moderator material structure, and an aluminum shell, arranged layer by layer from the inside out. The above-mentioned extra-reactor nuclear detection device not only improves the detection sensitivity of various types of detector assemblies by adding a moderator material structure and an aluminum shell to the detector assemblies, but also the aluminum shell prevents deformation of the moderator material structure under high radiation environments.

[0099] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for processing detection data from an external nuclear detection system, characterized in that, An application is made in an off-core nuclear detection system, the off-core nuclear detection system comprising an off-core nuclear detection device, a penetration component, and a nuclear instrument cabinet; the off-core nuclear detection device is connected to the nuclear instrument cabinet via the penetration component; the off-core nuclear detection device comprises several source range detector assemblies, several intermediate range detector assemblies, and several power range detector assemblies, and each of the source range detector assemblies, intermediate range detector assemblies, and power range detector assemblies can be fixed at the pressure vessel boundary of the reactor to be detected; each of the source range detector assemblies, intermediate range detector assemblies, and power range detector assemblies comprises a multi-layer detection structure; wherein the multi-layer detection structure comprises a detector body, a moderator material structure, and an aluminum shell arranged layer by layer from the inside out; the detection data processing method of the off-core nuclear detection system includes: Obtain the first theoretical count rate of the reference detector under the secondary source charge energy spectrum, and obtain the detection performance ratio of the source range detector and the reference detector in the extra-core nuclear detection system under the field plutonium-beryllium source test. The second theoretical count rate of the source range detector assembly is determined based on the ratio of the first theoretical count rate to the detection performance. The source range detector assembly is used to obtain a pre-estimated number rate when the neutron source of the reactor to be monitored is in a preset state. Based on the comparison between the second theoretical count rate and the estimated count rate, the current calculated count rate of the source range detector assembly is determined.

2. The detection data processing method of the extra-core nuclear detection system according to claim 1, characterized in that, The acquisition of the first theoretical count rate of the reference detector under the secondary source charge energy spectrum includes: The current first measured count rate of the reference detector under the on-site plutonium-beryllium source test is obtained, and the first B10 response number corresponding to the reference detector is obtained. The current detection efficiency is determined based on the ratio of the current first measured count rate to the first B10 response number. The second B10 reaction number of the reference detector assembly under the energy spectrum of the secondary source charge is obtained; wherein, the reference detector assembly is obtained by setting a moderator material structure around the outer wall of the reference detector and then setting an aluminum shell; The first theoretical count rate of the reference detector under the secondary source charge energy spectrum is determined based on the product of the second B10 reaction number and the current detection efficiency.

3. The detection data processing method of the extra-core nuclear detection system according to claim 1, characterized in that, Determining the second theoretical count rate of the source range detector assembly based on the ratio of the first theoretical count rate to the detection performance includes: The second theoretical count rate of the source range detector assembly is determined based on the product of the first theoretical count rate and the detection performance ratio.

4. The detection data processing method of the extra-core nuclear detection system according to claim 1, characterized in that, The step of obtaining the estimated number rate of the source range detector assembly when the neutron source of the reactor to be monitored is in a preset state includes: If the preset state corresponding to the neutron source of the reactor under monitoring is determined to include at least one of the planar source state, the bulk source state, and the simulated secondary neutron source state, then the estimated number rate corresponding to the neutron source of the reactor under monitoring in the preset state is obtained respectively.

5. The detection data processing method of the extra-core nuclear detection system according to claim 4, characterized in that, The determination of the current calculated count rate of the source range detector assembly based on the comparison result between the second theoretical count rate and the estimated count rate includes: The second theoretical count rate is compared with the estimated count rate corresponding to the neutron source of the reactor under the preset state. If the comparison results between the second theoretical count rate and the estimated count rate corresponding to the neutron source of the reactor under the preset state both satisfy the preset verification model conditions, then the second theoretical count rate is used as the current calculated count rate corresponding to the source range detector component.

6. The detection data processing method of the extra-core nuclear detection system according to claim 4, characterized in that, After the step of determining the current calculated count rate of the source range detector assembly based on the comparison result of the second theoretical count rate and the estimated count rate, the method further includes: The corresponding alarm count rate threshold is determined based on the current count rate of the source range detector component.

7. The detection data processing method of the extra-core nuclear detection system according to claim 6, characterized in that, The determination of the corresponding alarm count rate threshold based on the current calculated count rate of the source range detector component includes: Obtain the target preset count rate interval to which the current calculated count rate belongs among multiple preset count rate intervals, and use the target alarm count rate threshold of the target preset count rate interval as the alarm count rate threshold corresponding to the current calculated count rate.

8. The detection data processing method of the extra-core nuclear detection system according to claim 2, characterized in that, The process of obtaining the detection performance ratio of the source range detector and the reference detector in the off-pile nuclear detection system under on-site plutonium-beryllium source tests includes: Obtain the current third measured count rate of the source range detector in the off-pile nuclear detection system under the on-site plutonium-beryllium source test; The detection performance ratio is determined based on the ratio of the current third measured count rate to the current first measured count rate.

9. The detection data processing method of the extra-core nuclear detection system according to claim 5, characterized in that, The verification model condition is that the difference between the second theoretical count rate and the first, second, and third estimated count rates of the neutron source of the reactor to be monitored in the planar source state, the bulk source state, and the simulated secondary neutron source state, respectively, is less than a preset verification threshold.

10. The detection data processing method of the extra-core nuclear detection system according to claim 4, characterized in that, In the aforementioned source state, the source is a neutron source from the reactor between the source range detector and the guide tube; the simulated secondary neutron source state is the state in which secondary source neutrons are transported to the source range detector position after subcritical multiplication.

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