A self-powered neutron detector in-core calibration verification device

Abstract

The application belongs to the technical field of online measurement of neutron flux, and particularly relates to a self-powered neutron detector in-pile calibration verification device, which comprises a detection box body, an activated foil neutron detector and a thermocouple. The inside of the detection box body is provided with a first long through hole penetrating through the upper end face and the lower end face of the detection box body, and the self-powered neutron detector is arranged in the first long through hole. The activated foil neutron detector is arranged in the detection box body, located on one side of the first long through hole and not communicated with the first long through hole. The thermocouple is arranged in the detection box body, located on one side of the first long through hole and not communicated with the first long through hole. The self-powered neutron detector in-pile calibration verification device can accurately measure the neutron flux and the irradiation environment temperature of multiple points of the SPND, thereby calibrating the output signal of the SPND, ensuring the accuracy of the measurement results, and simultaneously, the multi-point arrangement design can verify the axial and radial consistency of the SPND at different positions, improve the reliability of the measurement results of the SPND, and provide reliable technical support for the accurate measurement of the neutron flux and the performance verification of the SPND.

Description

Technical Field

[0001] This invention relates to the field of online neutron flux measurement technology, specifically to a self-powered neutron detector in-reactor calibration and verification device. Background Technology

[0002] Online neutron flux measurement technology is still in its early stages in China. In research reactor applications such as neutron transmutation doping of single-crystal silicon and irradiation testing of RPV materials, precise control of the irradiated thermal neutron flux is required to achieve the target irradiation value. Currently, activated foils and self-powered neutron detectors are commonly used in engineering projects for measurement. The former method is an offline measurement method, which has many advantages such as high measurement accuracy, good flexibility, and minimal disturbance to the neutron field, but it cannot measure the change of thermal neutron flux rate over time. The latter method is an online measurement method, which can monitor the change of thermal neutron flux rate online and provide the thermal neutron flux of the irradiated sample in real time, thereby determining online whether the target irradiation value has been reached. A self-powered neutron detector (SPND) is a solid-state detector with a simple structure, long lifespan, small size, and no need for an external power source. It can be fixed inside the reactor for long-term measurement. However, the neutron field at different locations within the reactor varies, and this variation changes with factors such as control rod position movement, core loading changes, and fuel element burnup. As a result, the relationship between the SPND measurement signal and the actual neutron flux of the irradiated sample is not constant.

[0003] To further improve the research on neutron flux rate measurement technology and verify that the SPND neutron flux rate online measurement system can accurately monitor the irradiated thermal neutron flux of the corresponding channel in a thermal neutron radiation environment, it is necessary to conduct SPND output signal (current value) calibration (or standardization) tests to determine the SPND signal calibration factor and its variation law, conduct axial and radial consistency and reliability verification tests of multiple SPNDs, and conduct SPND response time tests to ensure its accuracy and reliability. Summary of the Invention

[0004] The technical problem to be solved by this invention is that the relationship between the SPND measurement signal and the actual neutron flux rate of the irradiated sample is not constant. The purpose is to provide a self-powered neutron detector in-reactor calibration and verification device, which realizes the calibration test of the SPND output signal (current value) to determine the signal calibration factor of the SPND and its variation law.

[0005] This invention is achieved through the following technical solution:

[0006] A self-sufficient neutron detector in-reactor calibration and verification device includes:

[0007] The detector housing has a first long through hole that penetrates the upper and lower surfaces of the detector housing, and a self-powered neutron detector is disposed in the first long through hole.

[0008] An activated foil neutron detector is disposed within the detector housing, located on one side of the first elongated through hole and not connected to the first elongated through hole;

[0009] A thermocouple is disposed inside the detection box, located on one side of the first elongated through hole and not connected to the first elongated through hole.

[0010] Specifically, the upper end face of the detection box is provided with an upper blind hole, the lower end face of the detection box is provided with a lower blind hole, and the activated foil neutron detector is disposed in the upper blind hole and the lower blind hole;

[0011] The calibration and verification device further includes an upper sealing assembly and a lower sealing assembly. The upper sealing assembly is sealed to the upper end of the probe box, and the lower sealing assembly is sealed to the lower end of the probe box. The upper sealing assembly is provided with an upper through hole corresponding to the first elongated through hole, and the lower sealing assembly is provided with a lower through hole corresponding to the first elongated through hole.

[0012] The upper sealing assembly is connected to the top cover of the irradiation channel via a support tube.

[0013] Optionally, the leads of the self-powered neutron detector, the activated foil neutron detector, and the thermocouple all extend out of the irradiation channel from inside the support tube.

[0014] Specifically, there are four first elongated through holes, the central axis of the first elongated through holes is parallel to the central axis of the detection box, and the four first elongated through holes are distributed in a ring along the central axis of the detection box.

[0015] The central axis of the upper blind hole is parallel to the central axis of the detection box. There are five upper blind holes, including one central upper blind hole and four outer upper blind holes. The central axis of the central upper blind hole coincides with the central axis of the detection box, and the four outer upper blind holes are distributed in a ring along the central axis of the detection box.

[0016] A first long through hole is provided on the line connecting the central axis of each of the outer upper blind holes and the central axis of the detection box;

[0017] The number of the lower blind holes is one, and the central axis of the lower blind hole coincides with the central axis of the detection box.

[0018] Optionally, the number of activated foil neutron detectors is 7, with 5 activated foil neutron detectors respectively disposed at the bottom of the upper blind hole in the middle and the upper blind hole in the outer, 1 activated foil neutron detector disposed in the lower blind hole, and the remaining 1 activated foil neutron detector disposed at the top of the upper blind hole in the middle.

[0019] Optionally, a pad tube is provided in the upper blind hole in the middle, which divides the upper blind hole in the middle into two independent cavities. The two activated foil neutron detectors are respectively arranged in the upper cavity and the lower cavity. The activated foil neutron detector located in the upper cavity is symmetrically arranged with the activated foil neutron detector located in the lower blind hole, and the center of symmetry is the activated foil neutron detector located in the lower cavity.

[0020] The activated foil neutron detectors located at the bottom of the upper blind hole in the middle and the bottom of the upper blind hole on the outer side coincide with the irradiation center plane.

[0021] Optionally, the detector housing has a second elongated through hole that penetrates the upper and lower surfaces of the detector housing, and the thermocouple is disposed in the second elongated through hole, with the thermocouple coinciding with the irradiation center surface.

[0022] Optionally, the number of the second elongated through holes is four, the central axis of the second elongated through holes is parallel to the central axis of the detection box, and the four second elongated through holes are distributed in a ring along the central axis of the detection box;

[0023] The distance between the second elongated through hole and the middle upper blind hole is equal to the distance between the outer upper blind hole and the middle upper blind hole, and the second elongated through hole and the outer upper blind hole are arranged alternately.

[0024] Optionally, the upper sealing assembly / lower sealing assembly includes: a pressure pad, a sealing gasket, and a nut. The sealing gasket is in contact with the upper and lower end faces of the detection box, and the nut is threaded to the upper and lower ends of the detection box. The nut applies a force toward the detection box to the sealing gasket through the pressure pad.

[0025] The sealing gasket and the pressure pad are provided with upper or lower through holes corresponding to the first elongated through hole and the second elongated through hole;

[0026] The nut is provided with a large through hole, and the projections of the first long through hole and the second long through hole are both located within the large through hole.

[0027] Optionally, the upper end of the detection box, the lower end of the detection box, and the nut are all provided with threadless areas for cutting and disassembling in the hot chamber.

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] This invention mainly includes a detector housing, an activated foil neutron detector, a self-powered neutron detector (SPND), and thermocouples. The detector housing has multiple elongated through-holes penetrating the upper and lower ends. The SPNDs are housed within these through-holes for real-time monitoring of the neutron flux. The activated foil neutron detector measures the neutron flux, and the thermocouples measure the temperature. Multiple SPNDs can be inserted simultaneously through these elongated through-holes, and multiple measurement points are arranged axially and radially to facilitate SPND output signal calibration and consistency verification tests.

[0030] This invention utilizes a self-powered neutron detector (SPND) in-core calibration and verification device to accurately measure the neutron flux rate and irradiation environment temperature at multiple points within the SPND, thereby calibrating the SPND output signal and ensuring the accuracy of the measurement results. Furthermore, the multi-point arrangement design allows for verification of the axial and radial consistency of the SPND at different locations, improving the reliability of the SPND measurement results and providing reliable technical support for the accurate measurement of neutron flux rate and the performance verification of the SPND. Attached Figure Description

[0031] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, but do not constitute a limitation on the embodiments of the present invention.

[0032] Figure 1 This is a schematic diagram of the structure of a self-powered neutron detector in-reactor calibration and verification device according to the present invention.

[0033] Figure 2 This is a top view schematic diagram of the positions of the neutron detector and thermocouple according to the present invention.

[0034] Figure 3 This is a side view schematic diagram of the positions of the neutron detector and thermocouple according to the present invention.

[0035] Figure 4 This is a schematic diagram of the overall structure of a self-powered neutron detector in-reactor calibration and verification device according to the present invention.

[0036] Figure 5 This is another distribution map of the measurement points according to the present invention.

[0037] Reference numerals: 1-Detector housing, 2-Self-powered neutron detector, 3-Activated foil neutron detector, 4-Thermocouple, 5-Upper sealing assembly, 6-Lower sealing assembly, 7-Support tube, 21-First long through hole, 31-Upper blind hole, 32-Lower blind hole, 33-Push tube, 311-Middle upper blind hole, 312-Outer upper blind hole. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0039] It should also be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0040] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "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 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. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0041] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] Where there is no conflict, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0043] Example 1

[0044] like Figure 1 , Figure 2 As shown, a self-powered neutron detector 2 in-pile calibration and verification device is provided, including: a detector housing 1, an activated foil neutron detector 3, and a thermocouple 4.

[0045] The detector housing 1 has a first long through hole 21 that penetrates the upper and lower surfaces of the detector housing 1. The self-powered neutron detector 2 is disposed inside the first long through hole 21.

[0046] The activated foil neutron detector 3 is disposed inside the detector housing 1, located on one side of the first long through hole 21 and not connected to the first long through hole 21;

[0047] Thermocouple 4 is disposed inside the detector housing 1, located on one side of the first elongated through hole 21 and not connected to the first elongated through hole 21. The detector housing 1 has a second elongated through hole that penetrates the upper and lower surfaces of the detector housing 1. Thermocouple 4 is disposed inside the second elongated through hole, and thermocouple 4 coincides with the irradiation center surface.

[0048] The Self-Powered Neutron Detector (SPND) is a solid-state detector that operates without an external power source. It measures neutron fluence by detecting the current generated by the reaction of neutrons with the detector material.

[0049] The Activation Foil Neutron Detector 3 utilizes the reaction of neutrons with specific materials to generate radioactive isotopes, and indirectly measures the neutron fluence by measuring the activity of these isotopes.

[0050] A thermocouple consists of two metal wires made of different materials, which measure temperature by utilizing the electromotive force difference between them at different temperatures.

[0051] The self-powered neutron detector 2 (SPND) is installed inside the first elongated through-hole 21 of the detector housing 1. It generates a current signal through the interaction between neutrons and the detector material, and this signal is proportional to the neutron fluence rate. Due to its self-powered characteristics, the SPND can perform long-term online monitoring within the reactor, providing real-time neutron fluence data.

[0052] An activated foil neutron detector 3 is housed within the detector housing 1. This detector indirectly reflects the neutron flux by measuring the activity of radioactive isotopes generated in a specific material after neutron irradiation. This method allows for the calibration and verification of SPND measurement results, determining their accuracy. The high precision and flexibility of the activated foil neutron detector 3 make it a reliable tool for SPND calibration.

[0053] Thermocouple 4 is used to measure the internal temperature environment of the device, and the electromotive force difference it generates reflects temperature changes. By monitoring temperature changes, the impact of ambient temperature on the measurement results of SPND and activated foil neutron detector 3 can be assessed, thereby ensuring the accuracy of the calibration and verification process.

[0054] During operation, the device is inserted into the radiation channel. The SPND is inserted into the first elongated through-hole 21 from its lower end. The activated foil neutron detector 3 and the thermocouple 4 are integrated into the detector housing 1, ultimately achieving the calibration and verification of the SPND output signal. The reference data provided by the activated foil neutron detector 3 is used to adjust and confirm the measurement results of the SPND, ensuring its accuracy and reliability under different environmental conditions.

[0055] Example 2

[0056] A self-powered neutron detector 2 in-pile calibration and verification device includes: a detector housing 1, an activated foil neutron detector 3, and a thermocouple 4.

[0057] The detector housing 1 has a first long through hole 21 that penetrates the upper and lower surfaces of the detector housing 1. The self-powered neutron detector 2 is disposed inside the first long through hole 21.

[0058] The activated foil neutron detector 3 is disposed inside the detector housing 1, located on one side of the first long through hole 21 and not connected to the first long through hole 21;

[0059] Thermocouple 4 is disposed inside the detector housing 1, located on one side of the first elongated through hole 21 and not connected to the first elongated through hole 21. The detector housing 1 has a second elongated through hole that penetrates the upper and lower surfaces of the detector housing 1. Thermocouple 4 is disposed inside the second elongated through hole, and thermocouple 4 coincides with the irradiation center surface.

[0060] like Figure 1 As shown, to enable the installation of the activated foil neutron detector 3, an upper blind hole 31 is provided on the upper end face of the detector housing 1, and a lower blind hole 32 is provided on the lower end face of the detector housing 1. The activated foil neutron detector 3 is installed in the upper blind hole 31 and the lower blind hole 32. The upper blind hole 31 and the lower blind hole 32 can ensure that the activated foil neutron detector 3 can accurately measure the neutron flux at different positions. The measurement results are used to calibrate the SPND signal to ensure the accuracy of SPND measurement.

[0061] The calibration and verification device also includes an upper sealing component 5 and a lower sealing component 6. The upper sealing component 5 is sealed to the upper end of the probe box 1, and the lower sealing component 6 is sealed to the lower end of the probe box 1. The upper sealing component 5 is provided with an upper through hole corresponding to the first long through hole 21, and the lower sealing component 6 is provided with a lower through hole corresponding to the first long through hole 21.

[0062] The upper sealing assembly 5 and the lower sealing assembly 6 are respectively sealed and connected to the upper and lower ends of the detection box 1. The upper and lower through holes, which match the corresponding elongated through holes on the detection box 1, ensure the sealing and stability of the device.

[0063] like Figure 4As shown, the upper sealing assembly 5 is connected to the top cover of the irradiation channel via the support tube 7. The support tube 7 not only provides physical support but also serves as a channel for the leads. The leads of the self-powered neutron detector 2, the activated foil neutron detector 3, and the thermocouple 4 all pass through the support tube 7 and out of the irradiation channel, thereby enabling all measurement signals to be accurately transmitted to the measurement equipment without interference from the external environment, achieving real-time monitoring and calibration of the SPND.

[0064] Example 3

[0065] like Figure 2 As shown, a detailed distribution map is provided.

[0066] There are four first long through holes 21. The central axis of the first long through holes 21 is parallel to the central axis of the detector box 1, and the four first long through holes 21 are distributed in a ring along the central axis of the detector box 1. The ring distribution ensures the uniformity and stability of the neutron flux rate measurement of the self-powered neutron detector 2 (SPND) in different orientations.

[0067] The central axis of the upper blind aperture 31 is parallel to the central axis of the detector housing 1. There are five upper blind apertures 31, including one central upper blind aperture 311 and four outer upper blind apertures 312. The central axis of the central upper blind aperture 311 coincides with the central axis of the detector housing 1, and the four outer upper blind apertures 312 are distributed in a ring along the central axis of the detector housing 1. The activated foil neutron detector 3 is installed in these upper blind apertures 31 to measure the neutron fluence at different positions. The SPND is calibrated and verified by these measurement data to ensure the accuracy of its measurement.

[0068] A first elongated through hole 21 is provided on the line connecting the central axis of each outer upper blind hole 312 and the central axis of the detector box 1; and the first elongated through hole 21 and the outer upper blind hole 312 are arranged opposite to each other, so that each SPND has a corresponding activated foil neutron detector 3 for relevant calibration.

[0069] There is one lower blind hole 32, and the central axis of the lower blind hole 32 coincides with the central axis of the detection box 1. The number of lower blind holes 32 is set according to the actual situation, and can be referred to Embodiments 4 and 5 for details.

[0070] There are four second long through holes. The central axis of the second long through holes is parallel to the central axis of the detector box 1, and the four second long through holes are distributed in a ring along the central axis of the detector box 1. The through holes of the second long through holes are used to place thermocouples 4 to monitor the temperature changes inside the device and help to assess the impact of temperature on the neutron detection and calibration process.

[0071] The distance between the second long through hole and the middle upper blind hole 311 is equal to the distance between the outer upper blind hole 312 and the middle upper blind hole 311. The second long through hole and the outer upper blind hole 312 are arranged alternately.

[0072] Example 4

[0073] In this embodiment, the number of activated foil neutron detectors 3 is 7, as an example. Figure 3 As shown, five activated foil neutron detectors 3 are respectively disposed at the bottom of the upper blind hole 311 in the middle and the upper blind hole 312 on the outer side, one activated foil neutron detector 3 is disposed in the lower blind hole 32, and the remaining one activated foil neutron detector 3 is disposed at the top of the upper blind hole 311 in the middle.

[0074] A pad tube 33 is provided inside the upper blind hole 311 in the middle. The pad tube 33 divides the upper blind hole 311 into two independent cavities, and two activated foil neutron detectors 3 are respectively arranged in the upper cavity and the lower cavity. The activated foil neutron detector 3 located in the upper cavity is symmetrically arranged with the activated foil neutron detector 3 located in the lower blind hole 32. The center of symmetry is the activated foil neutron detector 3 located in the lower cavity.

[0075] The activated foil neutron detector 3, located at the bottom of the upper blind hole 311 in the middle and the bottom of the upper blind hole 312 on the outer side, coincides with the irradiation center plane. The irradiation center plane refers to the plane in the reactor where neutron irradiation is strongest. By ensuring that the detector coincides with this plane, the most accurate neutron fluence data can be obtained, which can then be used to calibrate and verify the measurement results of the SPND.

[0076] The activated detector at the radial center of the detection box 1 is arranged at the top, middle and bottom positions of the SPND sensor, covering the length of the sensor. Multiple activated foil neutron detectors 3 of different materials are arranged at the middle position, and one activated foil neutron detector 3 is arranged at the top and bottom positions respectively. One activated foil neutron detector 3 is arranged at each of the four outermost positions (aligned with the plane of the SPND sensor).

[0077] In this embodiment, three activated foil neutron detectors 3 are arranged only at the position corresponding to the blind hole 311 in the middle.

[0078] Example 5

[0079] like Figure 5 As shown, in this embodiment, the number of activated foil neutron detectors 3 is 8. The corresponding structure needs to be modified.

[0080] The installation method of the seven activated foil neutron detectors 3 is the same as in Embodiment 4. The extra activated foil neutron detector 3 has two different installation structures.

[0081] One method is to add a pad tube 33, which is placed inside any one of the outer upper blind holes 312 and divides the outer upper blind hole 312 into two cavities. The added activated foil neutron detector 3 is located in the divided upper cavity.

[0082] Secondly, a lower blind hole 32 is added, which is positioned opposite to the outer upper blind hole 312. The added activated foil neutron detector 3 is installed inside this lower blind hole 32.

[0083] In addition, a structure with nine activated foil neutron detectors 3 is also provided.

[0084] The installation method of the seven activated foil neutron detectors 3 is the same as in Embodiment 4. The two extra activated foil neutron detectors 3 have three different installation structures.

[0085] One method is to add two pad tubes 33, which are respectively placed in any two outer upper blind holes 312, and divide the outer upper blind holes 312 into two cavities. The two added activated foil neutron detectors 3 are respectively located in the divided upper cavities.

[0086] Secondly, two lower blind holes 32 are added, and the positions of the lower blind holes 32 are opposite to the outer upper blind holes 312. The two newly added activated foil neutron detectors 3 are respectively placed in the newly added lower blind holes 32.

[0087] Thirdly, an additional pad tube 33 and a lower blind hole 32 are added. The pad tube 33 is placed inside any one of the outer upper blind holes 312, dividing the outer upper blind hole 312 into two cavities. The added activated foil neutron detector 3 is located in the divided upper cavity. The position of the added lower blind hole 32 is opposite to the outer upper blind hole 312, and the added activated foil neutron detector 3 is placed inside this lower blind hole 32.

[0088] In addition, a structure with 10 to 15 activated foil neutron detectors 3 is also provided. The specific structure will not be described in detail, but it can be simply understood as follows: apart from the three activated foil neutron detectors 3 located at the "upper, middle, and lower" positions of the detector box 1 in the center, and the four activated foil neutron detectors 3 located around the irradiation center surface, the remaining eight positions can be arbitrarily added with activated foil neutron detectors 3.

[0089] If it needs to be added to the upper part, a pad tube 33 is added inside the upper blind hole 312 on the outer side, and then the activated foil neutron detector 3 is added. If it needs to be added to the lower part, an additional lower blind hole 32 is required.

[0090] Example 6

[0091] The upper sealing assembly 5 / lower sealing assembly 6 includes a pressure pad, a sealing gasket, and a nut. The sealing gasket is fitted to the upper and lower end faces of the detector housing 1. The nut is threadedly connected to the upper and lower ends of the detector housing 1, and the nut applies a force towards the detector housing 1 to the sealing gasket through the pressure pad. The sealing gasket, fitted to the upper and lower end faces of the detector housing 1, serves a sealing function, preventing the internal neutron detector and other components from being affected by the external environment. The pressure pad is a gasket used to distribute pressure.

[0092] The sealing gasket and the pressure gasket are provided with upper or lower through holes corresponding to the first long through hole 21 and the second long through hole;

[0093] The nut has a large through hole, and the projections of the first long through hole 21 and the second long through hole are both located inside the large through hole, so that the leads of the neutron detector and the thermocouple 4 can pass through the nut in a concentrated manner, which facilitates the management and protection of the leads.

[0094] The upper end of the probe box 1, the lower end of the probe box 1, and the nut are all provided with threadless areas for cutting and disassembling in the hot chamber.

[0095] The upper and lower ends of the detector box 1 are sealed by threaded connection. To prevent the material from swelling and creeping during irradiation, which could lead to thread failure, a non-threaded cutting area is provided on the upper part of the upper and lower nuts, so that the detector box can be cut and disassembled in the hot chamber.

[0096] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0097] 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 application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0098] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above invention, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A self-sufficient neutron detector in-reactor calibration and verification device, characterized in that, include: The detector box (1) has a first long through hole (21) that penetrates the upper and lower surfaces of the detector box (1), and the self-powered neutron detector (2) is installed inside the first long through hole (21). An activated foil neutron detector (3) is disposed inside the detector housing (1), located on one side of the first long through hole (21) and not connected to the first long through hole (21); Thermocouple (4) is disposed inside the detection box (1), located on one side of the first long through hole (21) and not connected to the first long through hole (21); The upper end face of the detector box (1) is provided with an upper blind hole (31), and the lower end face of the detector box (1) is provided with a lower blind hole (32). The activated foil neutron detector (3) is disposed in the upper blind hole (31) and the lower blind hole (32). The calibration and verification device further includes an upper sealing component (5) and a lower sealing component (6). The upper sealing component (5) is sealed to the upper end of the probe box (1), and the lower sealing component (6) is sealed to the lower end of the probe box (1). The upper sealing component (5) is provided with an upper through hole corresponding to the first long through hole (21), and the lower sealing component (6) is provided with a lower through hole corresponding to the first long through hole (21). The upper sealing assembly (5) is connected to the top cover of the irradiation channel via a support tube (7); The number of the first long through holes (21) is four. The central axis of the first long through holes (21) is parallel to the central axis of the detection box (1), and the four first long through holes (21) are distributed in a ring along the central axis of the detection box (1). The central axis of the upper blind hole (31) is parallel to the central axis of the detection box (1). There are five upper blind holes (31), including one central upper blind hole (311) and four outer upper blind holes (312). The central axis of the central upper blind hole (311) coincides with the central axis of the detection box (1). The four outer upper blind holes (312) are arranged in a ring along the central axis of the detection box (1). Each of the outer upper blind holes (312) has a first long through hole (21) on the line connecting the central axis of the outer blind hole (312) and the central axis of the detection box (1). The number of the lower blind hole (32) is 1, and the central axis of the lower blind hole (32) coincides with the central axis of the detection box (1); The detector housing (1) has a second long through hole that penetrates the upper and lower surfaces of the detector housing (1). The thermocouple (4) is installed in the second long through hole and coincides with the irradiation center surface. There are four second long through holes. The central axis of the second long through holes is parallel to the central axis of the detector housing (1), and the four second long through holes are distributed in a ring along the central axis of the detector housing (1). The distance between the second elongated through hole and the middle upper blind hole (311) is equal to the distance between the outer upper blind hole (312) and the middle upper blind hole (311), and the second elongated through hole and the outer upper blind hole (312) are arranged alternately.

2. The self-powered neutron detector in-reactor calibration and verification device according to claim 1, characterized in that, The leads of the self-powered neutron detector (2), the activated foil neutron detector (3), and the thermocouple (4) all pass through the irradiation channel from the support tube (7).

3. The self-powered neutron detector in-reactor calibration and verification device according to claim 1, characterized in that, The number of activated foil neutron detectors (3) is 7. Five of the activated foil neutron detectors (3) are respectively disposed at the bottom of the upper blind hole (311) in the middle and the upper blind hole (312) on the outside. One activated foil neutron detector (3) is disposed in the lower blind hole (32). The remaining one activated foil neutron detector (3) is disposed at the top of the upper blind hole (311) in the middle.

4. The self-powered neutron detector in-reactor calibration and verification device according to claim 3, characterized in that, A pad tube (33) is provided inside the upper blind hole (311) in the middle. The pad tube (33) divides the upper blind hole (311) in the middle into two independent cavities. The two activated foil neutron detectors (3) are respectively arranged in the upper cavity and the lower cavity. The activated foil neutron detector (3) located in the upper cavity is symmetrically arranged with the activated foil neutron detector (3) located in the lower blind hole (32). The center of symmetry is the activated foil neutron detector (3) located in the lower cavity. The activated foil neutron detector (3) located at the bottom of the upper blind hole (311) in the middle and at the bottom of the upper blind hole (312) in the outer coincides with the irradiation center plane.

5. The self-powered neutron detector in-reactor calibration and verification device according to claim 1, characterized in that, The upper sealing assembly (5) / the lower sealing assembly (6) includes: a pressure pad, a sealing pad and a nut. The sealing pad is in contact with the upper and lower end faces of the detection box (1). The nut is threaded to the upper and lower ends of the detection box (1). The nut applies a force toward the detection box (1) to the sealing pad through the pressure pad. The sealing gasket and the pressure pad are provided with upper or lower through holes corresponding to the first elongated through hole (21) and the second elongated through hole; The nut is provided with a large through hole, and the projections of the first long through hole (21) and the second long through hole are both located in the large through hole.

6. The self-powered neutron detector in-reactor calibration and verification device according to claim 5, characterized in that, The upper end of the probe box (1), the lower end of the probe box (1), and the nut are all provided with a threadless area for cutting and disassembling in the hot chamber.

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