Method for arranging neutron detectors

Abstract

This invention relates to a neutron detector placement method, which includes performing nuclear reactor modeling; calculating the neutron count rate distribution below the containment vessel based on the modeling results, wherein the neutron count rate distribution represents the level of the neutron count rate at each location in the nuclear reactor; obtaining the number of neutrons corresponding to each location based on the neutron count rate distribution; if the number of neutrons corresponding to a certain location is greater than or equal to the lower limit of the neutron detector, then that location is designated as a first candidate location, wherein the lower limit of the neutron detector is the minimum number of neutrons that the neutron detector can detect; and selecting a target location for placing the neutron detector based on the first candidate location. Because the shielding in the area below the containment vessel is relatively thin, placing the neutron detector in the outer region below the containment vessel makes it easier for the neutron detector placed outside the reactor to obtain a higher count. By determining the first candidate location, a target location for placing the neutron detector can be selected from the first candidate location.

Description

Technical Field

[0001] This invention relates to the field of neutron source detection technology, and in particular to a method for arranging neutron detectors. Background Technology

[0002] like Figure 1 and Figure 2 As shown, a nuclear reactor includes a neutron source, core fuel assemblies 100, a shield 200, a containment vessel 300, and a neutron detector 400. The shield 200 encloses the core fuel assembly 100 and is housed within the containment vessel 300. The neutron detector 400 is horizontally positioned outside the containment vessel 300. The neutron source is located within the core fuel assembly 100. The neutrons generated by the neutron source undergo subcritical multiplication to produce a sufficient number of neutrons. The neutron detector 400 monitors the neutron flux distribution, thereby calculating the nuclear power of the nuclear reactor. However, because the shield 200 is thick and absorbs neutrons, the number of neutrons reaching the outside of the reactor is small, resulting in very few neutrons detected by the neutron detector 400, making it difficult to effectively monitor the neutron flux of the nuclear reactor. Summary of the Invention

[0003] Therefore, it is necessary to provide a method for arranging neutron detectors to address the issue of neutron detector placement.

[0004] A method for arranging neutron detectors, comprising:

[0005] A nuclear reactor model is performed, and the neutron count rate distribution below the containment vessel is calculated based on the modeling results. The neutron count rate distribution represents the level of the neutron count rate at each location of the nuclear reactor.

[0006] The number of neutrons at each position is obtained according to the neutron count rate distribution. If the number of neutrons at a certain position is greater than or equal to the lower limit of the neutron detector, then the position is taken as the first candidate position. The lower limit of the neutron detector is the minimum number of neutrons that the neutron detector can detect.

[0007] The target location for arranging the neutron detector is selected based on the first alternative location.

[0008] In one embodiment, calculating the neutron count rate distribution below the containment based on the modeling results includes:

[0009] The neutron fluence rate distribution beneath the containment structure is directly derived from the modeling results; and

[0010] The neutron count rate distribution is calculated from the neutron fluence rate distribution.

[0011] In one embodiment, the neutron count rate distribution is calculated by multiplying the neutron fluence rate distribution by the sensitivity of the neutron detector.

[0012] In one embodiment, when modeling the nuclear reactor, the position of the neutron source in the core fuel assembly is determined according to the loading scheme of the nuclear reactor, and the modeling is completed using neutron transport software based on the position information of the neutron source and the loading scheme.

[0013] In one embodiment, if there are multiple first candidate locations, then selecting the target location for arranging the neutron detector based on the first candidate locations includes:

[0014] Obtain the number of neutrons corresponding to each of the first candidate positions, and select the first candidate position corresponding to the largest number of neutrons as the target position for deploying the neutron detector.

[0015] In one embodiment, selecting the target location for arranging the neutron detector based on the first candidate location includes:

[0016] Each time, it is determined whether the neutron detector, when arranged at each of the first candidate positions, will interfere with other structures, and the first candidate position corresponding to which no interference occurs is selected as the second candidate position; and

[0017] The target location for arranging the neutron detector is selected based on the second alternative location.

[0018] In one embodiment, if multiple second candidate locations exist, selecting the target location for arranging the neutron detector based on the second candidate locations includes:

[0019] Obtain the number of neutrons corresponding to each of the second candidate locations, and select the second candidate location with the largest number of neutrons as the target location for deploying the neutron detector; or

[0020] The temperature of each of the second candidate locations is obtained, and the second candidate location corresponding to the normal operating temperature of the neutron detector is selected as the third candidate location; and the target location for arranging the neutron detector is selected according to the third candidate location.

[0021] In one embodiment, if there are multiple third alternative locations, then selecting the target location for arranging the neutron detector based on the third alternative locations includes:

[0022] Obtain the number of neutrons corresponding to each of the third candidate positions, and select the third candidate position corresponding to the largest number of neutrons as the target position for arranging the neutron detector.

[0023] In one embodiment, the parameters of the neutron detector are adjusted before the neutron detector is positioned at the target location below the containment building.

[0024] In one embodiment, during modeling, the containment vessel and the shield are set as cylindrical, and the neutron count rate distribution below the cylindrical containment vessel is calculated.

[0025] The beneficial effects of this invention are:

[0026] The aforementioned neutron detector placement method first performs nuclear reactor modeling, then calculates the neutron count rate distribution below the containment vessel based on the modeling results. In other words, the neutron count rate distribution on the outer side of the containment vessel bottom is obtained through modeling, thus revealing the neutron count rate levels in each region below the containment vessel. The neutron count rate distribution is used to obtain the neutron count at each location on the outer side of the containment vessel bottom. This neutron count at each location is then compared to the lower limit of the neutron detector. If the neutron count at a certain location is greater than or equal to the lower limit of the neutron detector, it indicates that the neutron detector can detect neutrons at that location, and this location is selected as the first candidate location. The target location for placing the neutron detector is then chosen based on this first candidate location. Because the shielding in the region below the containment vessel is relatively thin and its neutron absorption shielding effect is weak, placing the neutron detector in the outer region below the containment vessel makes it easier for the off-site neutron detector to obtain a higher count, thereby facilitating effective monitoring of the neutron flux rate of the nuclear reactor. By determining the first alternative location, a target location where a neutron detector can be placed can be selected from the first alternative location. Attached Figure Description

[0027] Figure 1 This is a first-view structural diagram of a nuclear reactor in the background art.

[0028] Figure 2 This is a first-view structural diagram of a nuclear reactor in the background art.

[0029] Figure 3 This is a schematic diagram of a neutron detector arranged below the containment building according to an embodiment of the present invention;

[0030] Figure 4 A flowchart illustrating a neutron detector arrangement method provided in an embodiment of the present invention.

[0031] In the picture:

[0032] 100. Core fuel assemblies;

[0033] 200. Shielding components;

[0034] 300. Containment structure;

[0035] 400. Neutron detector. Detailed Implementation

[0036] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0037] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0039] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0041] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0042] like Figure 3 and Figure 4 As shown, this embodiment of the invention provides a method for arranging electronic detectors, which includes: performing nuclear reactor modeling; calculating the neutron count rate distribution below the containment vessel 300 based on the modeling results, wherein the neutron count rate distribution represents the level of the neutron count rate at each location of the nuclear reactor; obtaining the number of neutrons corresponding to each location based on the neutron count rate distribution; if the number of neutrons corresponding to a certain location is greater than or equal to the lower limit of the neutron detector 400, then the location is selected as a first candidate location, wherein the lower limit of the neutron detector 400 is the minimum number of neutrons that the neutron detector 400 can detect; and selecting a target location for arranging the neutron detector 400 based on the first candidate location.

[0043] The above-described neutron detector deployment method first involves modeling the nuclear reactor, then calculating the neutron count rate distribution below the containment vessel 300 based on the modeling results. In other words, the neutron count rate distribution on the outer side of the bottom of the containment vessel 300 is obtained through the modeling results, thus revealing the neutron count rate levels in each region below the containment vessel 300. The number of neutrons at each location on the outer side of the bottom of the containment vessel 300 is obtained through the neutron count rate distribution. This number is then compared to the lower limit of the neutron detector 400. If the number of neutrons at a location is less than the lower limit of the neutron detector 400, it is determined that the neutron detector 400 cannot detect neutrons at that location. If the number of neutrons at a location is greater than or equal to the lower limit of the neutron detector 400, it indicates that the neutron detector 400 can detect neutrons at that location, and this location is designated as the first candidate location. The target location for deploying the neutron detector 400 is then selected based on the first candidate location. The neutron detector arrangement method provided in this application addresses the issue that the shielding below the containment vessel 300 is relatively thin, resulting in weak neutron absorption and shielding. Therefore, the neutron detector 400 is arranged on the outer side below the containment vessel 300, making it easier for the externally located neutron detector 400 to achieve higher neutron counts, thus facilitating effective monitoring of the nuclear reactor's neutron flux rate. By identifying a first candidate location, a target location for neutron detector 400 can be selected from this first candidate location.

[0044] It should be noted that the neutron count rate refers to the number of neutrons that the neutron detector 400 can detect per unit time. The neutron count rate distribution represents the level of the neutron count rate in each region of the nuclear reactor. The neutron count rate distribution is calculated through modeling results, which means that the number of neutrons distributed in each region below the containment vessel 300 is obtained. The lower limit of the neutron detector 400 is the minimum number of neutrons that the neutron detector 400 can detect. By comparing the number of neutrons at the current location with the lower limit of the neutron detector 400, it can be determined whether the current location can be used as the first alternative location.

[0045] In some embodiments, the parameters of the neutron detector 400 are adjusted before it is positioned at the target location below the containment vessel 300. Before actually positioning the neutron detector 400 at its current location, the parameters of the neutron detector 400 need to be adjusted so that multiple parameters of the neutron detector 400 meet the actual operational requirements and improve the detection accuracy of the neutron detector 400.

[0046] In some embodiments, during modeling, the containment vessel 300 and shielding member 200 are set as cylindrical shapes, and the neutron count rate distribution below the cylindrical shape is calculated. Setting both the containment vessel 300 and shielding member 200 as cylindrical shapes conforms to the actual shapes of the containment vessel 300 and shielding member 200 in a nuclear reactor, improving the realism of the modeling. Calculating the neutron count rate distribution below the cylindrical shape is equivalent to calculating the actual neutron count rate distribution below the containment vessel 300, thus improving the accuracy of the modeling results.

[0047] Specifically, when modeling a nuclear reactor, the location of the neutron source within the fuel assembly 100 in the reactor core is determined based on the reactor's loading scheme. Then, neutron transport software is used to complete the modeling based on the neutron source's location and loading scheme. First, the reactor core loading scheme and neutron source arrangement scheme are obtained by consulting relevant literature, thus determining the neutron source's location within the fuel assembly 100. Then, based on the neutron source's location and loading scheme, neutron transport software is used to complete the modeling, and the neutron count rate distribution can be calculated from the modeling results.

[0048] More specifically, neutron transport software, such as Monte Carlo software or discrete ordinate software, can be used for nuclear reactor modeling. The specific modeling steps are conventional techniques in this field and will not be elaborated here.

[0049] In some embodiments, the neutron fluence rate distribution below containment 300 is directly obtained from the modeling results, and the neutron count rate distribution is calculated from the neutron fluence rate distribution. After modeling is completed using neutron transport software, the neutron fluence rate distribution below containment 300 can be directly obtained from the modeling results, and the neutron count rate distribution can be calculated by substituting the neutron fluence rate distribution into the formula. It is understood that directly obtaining the neutron fluence rate distribution below containment 300 from the modeling results is a conventional technique in this field and will not be elaborated further here.

[0050] It should be noted that neutron flux refers to the quotient obtained by dividing the number of neutrons received at a certain point in space per unit time, regardless of their direction of entry into a small sphere centered at that point, by the maximum cross-sectional area of ​​that sphere. The unit is n / (cm^2·s). Neutron flux distribution refers to the level of neutron flux at various locations in the core of a nuclear reactor.

[0051] Specifically, the neutron count rate distribution is calculated by multiplying the neutron flux rate distribution by the sensitivity of the neutron detector 400. According to the formula... The neutron count rate distribution was calculated, where, Let ε represent the neutron flux rate distribution, and ε be the sensitivity of the neutron detector 400. The neutron flux rate distribution can be directly obtained from the modeling results. The sensitivity of the neutron detector 400 can be obtained by referring to its technical manual. Substituting the neutron flux rate distribution and the sensitivity of the neutron detector 400 into the formula, the neutron count rate distribution can be obtained.

[0052] It should be noted that, according to common knowledge in the field, the sensitivity of the neutron detector 400 is... Where C is the neutron count rate. Since it is the neutron fluence rate, the formula can be derived. Therefore, the neutron count rate distribution

[0053] After obtaining the first candidate location, in some embodiments, any one of the multiple first candidate locations can be directly selected as the target location for deploying the neutron detector 400. Alternatively, in some embodiments, the target location of the neutron detector 400 can be selected based on the number of neutrons corresponding to each of the first candidate locations.

[0054] Specifically, in some embodiments, if multiple first candidate locations exist, selecting the target location for neutron detector 400 based on the first candidate locations includes: obtaining the number of neutrons corresponding to each first candidate location, and selecting the first candidate location with the largest number of neutrons as the target location for neutron detector 400. Multiple first candidate locations for neutron detector 400 can be obtained by determining the number of neutrons at multiple locations below the containment vessel 300 and the lower limit of the neutron detector 400. Among these multiple first candidate locations, the number of neutrons corresponding to each first candidate location is obtained, and the first candidate location with the largest number of neutrons is selected as the target location for neutron detector 400. It is understood that when neutron detector 400 is placed at the first candidate location with the largest number of neutrons, that is, at that location, the number of neutrons detected by neutron detector 400 is the highest, which facilitates effective monitoring of the neutron flux rate of the nuclear reactor.

[0055] Furthermore, in some embodiments, when multiple first candidate locations are obtained, the first candidate locations can be further filtered before selecting a target location for arranging the neutron detector 400 from the filtered locations. For example, in some embodiments, selecting a target location for arranging the neutron detector 400 based on the first candidate locations includes determining whether the neutron detector 400 would interfere with other structures if arranged in each of the first candidate locations, and designating the first candidate location where no interference occurs as a second candidate location; and selecting a target location for arranging the neutron detector 400 based on the second candidate locations. After obtaining the first candidate locations, if there are multiple first candidate locations, it is determined whether the neutron detector 400 would interfere with other structural components or devices if arranged in each of the first candidate locations. If the neutron detector 400 does not interfere with other structural components or devices, the first candidate location where no interference occurs is designated as a second candidate location, and a target location for arranging the neutron detector 400 is selected based on the second candidate location. For example, the first candidate locations include locations A, B, and C. It is determined sequentially whether the neutron detector 400 would interfere with other structural components or equipment when placed at locations A, B, and C. Assuming that the neutron detector 400 does not interfere with other structural components or equipment when placed at locations A and B, but interferes when placed at location C, then locations A and B are considered as the second candidate locations; that is, locations A and B can be used as target locations for placing the neutron detector 400. This further narrows down the possible placement range of the neutron detector 400, thus avoiding placing it in a location that would interfere with other structural components or equipment.

[0056] After obtaining the second alternative locations, in some embodiments, any one of the multiple second alternative locations can be directly selected as the target location for deploying the neutron detector 400. Alternatively, in some embodiments, the target location for the neutron detector 400 can be selected based on the neutron count corresponding to each second alternative location. Specifically, in some embodiments, if multiple second alternative locations exist, selecting the target location for deploying the neutron detector 400 based on the second alternative locations includes: obtaining the neutron count corresponding to each second alternative location, and selecting the second alternative location with the highest neutron count as the target location for deploying the neutron detector 400. It is understood that when the neutron detector 400 is deployed at the second alternative location with the highest neutron count, that is, at that location, the neutron detector 400 detects the highest number of neutrons, and the neutron detector 400 will not interfere with other structural components or equipment, thus facilitating effective monitoring of the neutron flux rate of the nuclear reactor.

[0057] In some embodiments, after obtaining the second candidate locations, the target location of the neutron detector 400 can be selected based on the temperature at each of the second candidate locations. Specifically, in some embodiments, if there are multiple second candidate locations, selecting the target location for neutron detector 400 based on the second candidate locations may further include: obtaining the temperature of each second candidate location, and using the second candidate location that meets the normal operating temperature of neutron detector 400 as the third candidate location; and selecting the target location for neutron detector 400 based on the third candidate location. After obtaining the second candidate locations, it is further determined whether the temperature at the second candidate location meets the normal operating temperature range of neutron detector 400. If the temperature at the second candidate location does not meet the normal operating temperature range of neutron detector 400, then the second candidate location cannot be used to place neutron detector 400. If the temperature at the second candidate location meets the normal operating temperature range of neutron detector 400, then the second candidate location that meets the normal operating temperature of neutron detector 400 is used as the third candidate location. For example, the second candidate locations include location A and location B, and the temperatures at locations A and B are determined sequentially. Assuming that the temperature at location A meets the normal operating temperature of the neutron detector 400, while the temperature at location B does not, then location A is selected as the third alternative location; that is, location A can be considered as the target temperature for arranging the neutron detector 400. This further narrows down the possible placement range of the neutron detector 400, thus avoiding not only placing the neutron detector 400 in a location that would interfere with other structural components or equipment, but also avoiding placing the neutron detector 400 in a location that does not meet its operating temperature requirements.

[0058] It should be noted that in some embodiments, after obtaining multiple first candidate positions, multiple positions that can meet the normal operating temperature of the neutron detector 400 can be selected first, and then positions that can not interfere with other structural components or equipment can be selected as third candidate positions. No restrictions are imposed here.

[0059] After obtaining the third alternative location, in some embodiments, any one of the multiple third alternative locations can be directly selected as the target location for deploying the neutron detector 400; or, in some embodiments, the target location for the neutron detector 400 can be selected based on the number of neutrons corresponding to each of the third alternative locations. Specifically, in some embodiments, if there are multiple third alternative locations, selecting the target location for deploying the neutron detector 400 based on the third alternative locations includes: obtaining the number of neutrons corresponding to each third alternative location, and selecting the third alternative location with the largest number of neutrons as the target location for deploying the neutron detector 400. If there are multiple third alternative locations, and the neutron detector 400 deployed at any of the multiple third alternative locations can meet the requirement of not interfering with other structural components or equipment, and the temperature at the multiple third alternative locations is within the normal operating temperature range of the neutron detector 400, then after three judgments, the target location is selected from the multiple third alternative locations, and the location with the largest number of neutrons among the multiple third alternative locations is the target location for deploying the neutron detector 400.

[0060] The neutron detector 400 arrangement method provided in this embodiment determines that the neutron detector 400 needs to be arranged below the containment building 300.

[0061] S1. Based on the location information and loading scheme of the neutron source, neutron transport software is used to complete the modeling, and then the neutron flux distribution is obtained based on the modeling results.

[0062] S2, Substitute the neutron flux distribution and the sensitivity of the neutron detector 400 into the formula In this way, the neutron count rate distribution can be calculated;

[0063] S3. Obtain the number of neutrons corresponding to each position according to the neutron count rate distribution, and determine whether the number of neutrons corresponding to a certain position is greater than or equal to the lower limit of the neutron detector 400. If so, the position is taken as the first candidate position. If not, it is determined that the neutron detector 400 cannot be placed at the position, and the previous step is returned to re-determine.

[0064] S4. If there are multiple first alternative positions, determine whether the neutron detector 400 will interfere with other structures when it is placed in each first alternative position. If not, the position is used as the second alternative position. If so, it is determined that the neutron detector 400 cannot be placed in the position.

[0065] S5. If there are multiple second alternative locations, obtain the temperature of each second alternative location, and determine whether the neutron detector 400 meets the normal operating temperature of the neutron detector 400 when it is placed in each second alternative location. If yes, the location is used as the third alternative location; otherwise, it is determined that the neutron detector 400 cannot be placed in the location.

[0066] S6. If there are multiple third alternative locations, obtain the number of neutrons corresponding to each third alternative location, and select the third alternative location with the largest number of neutrons as the target location for deploying the neutron detector 400.

[0067] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for arranging neutron detectors, characterized in that, include: A nuclear reactor model is performed, and the neutron count rate distribution below the containment vessel (300) is calculated based on the modeling results. The neutron count rate distribution is the level of the neutron count rate at each location of the nuclear reactor. The number of neutrons at each position is obtained according to the neutron count rate distribution. If the number of neutrons at a certain position is greater than or equal to the lower limit of the neutron detector, then the position is taken as the first candidate position. The lower limit of the neutron detector (400) is the minimum number of neutrons that the neutron detector can detect. The target location for arranging the neutron detector (400) is selected based on the first alternative location; The step of selecting the target location for arranging the neutron detector (400) based on the first candidate location includes: It is determined whether the neutron detector (400) will interfere with other structures when it is arranged in each of the first candidate positions, and the first candidate position that will not cause interference is selected as the second candidate position; and The target location for arranging the neutron detector (400) is selected according to the second alternative location; If multiple second alternative locations exist, the step of selecting the target location for arranging the neutron detector (400) based on the second alternative locations includes: Obtain the number of neutrons corresponding to each of the second candidate positions, and select the second candidate position corresponding to the maximum number of neutrons as the target position for arranging the neutron detector (400); or The temperature of each of the second candidate locations is obtained, and the second candidate location corresponding to the normal operating temperature of the neutron detector (400) is selected as the third candidate location; and the target location for arranging the neutron detector (400) is selected according to the third candidate location. If multiple third alternative locations exist, the target location for arranging the neutron detector (400) is selected based on the third alternative locations, including: Obtain the number of neutrons corresponding to each of the third candidate positions, and select the third candidate position corresponding to the largest number of neutrons as the target position for arranging the neutron detector (400).

2. The neutron detector arrangement method according to claim 1, characterized in that, The calculation of the neutron count rate distribution below the containment structure (300) based on the modeling results includes: The neutron fluence rate distribution below the containment structure (300) is directly derived from the modeling results; and The neutron count rate distribution is calculated from the neutron fluence rate distribution.

3. The neutron detector arrangement method according to claim 2, characterized in that, The neutron count rate distribution is calculated by multiplying the neutron flux rate distribution with the sensitivity of the neutron detector (400).

4. The neutron detector arrangement method according to claim 2, characterized in that, When modeling the nuclear reactor, the position of the neutron source in the core fuel assembly (100) is determined according to the loading scheme of the nuclear reactor. The modeling is completed using neutron transport software based on the position information of the neutron source and the loading scheme.

5. The neutron detector arrangement method according to claim 1, characterized in that, If multiple first candidate locations exist, the target location for arranging the neutron detector (400) based on the first candidate locations includes: Obtain the number of neutrons corresponding to each of the first candidate positions, and select the first candidate position corresponding to the largest number of neutrons as the target position for arranging the neutron detector (400).

6. The neutron detector arrangement method according to claim 1, characterized in that, Before placing the neutron detector (400) at the target location below the containment building (300), adjust the parameters of the neutron detector (400).

7. The neutron detector arrangement method according to claim 1, characterized in that, During modeling, the containment vessel (300) and shield (200) are set as cylindrical, and the neutron count rate distribution below the cylindrical containment vessel (300) is calculated.

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