Method and device for monitoring corrosion of a liquid metal reactor installation

Abstract

This application discloses a corrosion monitoring method and device for a liquid metal reactor device. The method includes: in a corrosive environment where the liquid metal reactor device is filled with liquid metal, measuring the radioactivity of a tracer nuclide in the same target area at multiple time points using a gamma detector to obtain the net count rate of the tracer nuclide at each time point; performing decay correction on the first and second net count rates based on the time interval between the first and second time points and the measurement duration of a single radioactivity measurement; and determining the thickness reduction of the device wall in the target area based on a preset calibration correspondence, the corrected first net count rate, and the corrected second net count rate; wherein the calibration correspondence is the correspondence between the ratio of net count rates and the thickness. This application enables corrosion monitoring of the liquid metal reactor device wall during normal operation of the nuclear reactor.

Description

Technical Field

[0001] This application relates to the field of nuclear power technology, and in particular to a corrosion monitoring method and device for a liquid metal reactor. Background Technology

[0002] Currently, based on the advantages of liquid metals, such as low melting point, high boiling point, good thermal conductivity, and high chemical stability, liquid metals are usually used as coolants in the primary loop of nuclear reactors, such as pure lead, lead-bismuth alloys, and lead-lithium alloys.

[0003] However, liquid metals can be extremely corrosive to common structural materials (such as iron-based steel and nickel-based alloys) at high temperatures, which can lead to thinning and even perforation of the walls of devices that hold liquid metals, affecting the integrity of the device's boundaries and potentially causing liquid metal leaks.

[0004] Because liquid metal operates at high ambient temperatures and is opaque, conventional optical imaging techniques such as CCD cameras and holographic imaging cannot be used to monitor for material corrosion. Currently, corrosion is typically assessed after operation is completed, but the results are subject to a time lag, posing challenges to the monitoring and maintenance of nuclear reactors. Summary of the Invention

[0005] This application provides a corrosion monitoring method and device for liquid metal reactor devices, aiming to solve the technical problem in related technologies that it is impossible to monitor material corrosion during the normal operation of liquid metal reactor devices.

[0006] In a first aspect, embodiments of this application provide a corrosion monitoring method for a liquid metal reactor device, the method comprising: In a corrosive environment where a liquid metal reactor is filled with liquid metal, the radioactivity of tracer nuclides is measured at multiple time points in the same target area using a gamma detector to obtain the net count rate of the tracer nuclides at each time point; wherein, the target area is the part of the device wall of the liquid metal reactor containing the tracer nuclides. Based on the time interval between the first and second time nodes and the measurement duration of a single radioactivity measurement, the first net count rate corresponding to the first time node is corrected to obtain the corrected first net count rate. Based on the time interval between the first and second time nodes and the measurement duration of a single radioactivity measurement, the second net count rate corresponding to the second time node is decay-corrected to obtain the corrected second net count rate. Based on the preset calibration correspondence, the corrected first net count rate, and the corrected second net count rate, the thickness reduction of the device wall in the target area is determined; wherein, the calibration correspondence is the correspondence between the ratio of net count rates and the thickness.

[0007] In one embodiment of this application, the step of measuring the radioactivity of a tracer nuclide in the same target area at multiple time points using a gamma detector to obtain the net count rate of the tracer nuclide at each time point includes: At each time point, the gamma spectrum of the target region is collected by a gamma detector, and the characteristic gamma-ray peaks of the tracer nuclide are extracted from the gamma spectrum to determine the total count of the tracer nuclide. The net count rate of the tracer nuclide is calculated based on the total count of the tracer nuclide, the pre-acquired background count, and the corresponding measurement time.

[0008] In one embodiment of this application, calculating the net count rate corresponding to the tracer nuclide based on the total count of the tracer nuclide, the pre-acquired background count, and the corresponding measurement time includes: The total count of the tracer nuclides is divided by the corresponding measurement duration to obtain the total count rate of the tracer nuclides; Divide the pre-acquired background count by the corresponding measurement duration to obtain the background count rate; The net count rate corresponding to the tracer nuclide is obtained by subtracting the background count rate from the total count rate of the tracer nuclide.

[0009] In one embodiment of this application, the first time point is the initial moment when the liquid metal reactor device starts operating; The step of correcting the first net count rate corresponding to the first time node based on the time interval between the first and second time nodes and the measurement duration of a single radioactivity measurement, to obtain the corrected first net count rate, includes: The first decay correction coefficient corresponding to the first time node is calculated based on the time interval between the first time node and the second time node and the first decay correction coefficient algorithm. The second decay correction coefficient corresponding to the first time node is calculated based on the measurement duration of a single radioactivity measurement and the second decay correction coefficient algorithm. The first net count rate is decay-corrected based on the first decay correction coefficient and the second decay correction coefficient corresponding to the first time node to obtain the corrected first net count rate.

[0010] In one embodiment of this application, the first time point is the initial moment when the liquid metal reactor device starts operating; The step of performing decay correction on the second net count rate corresponding to the second time node based on the time interval between the first and second time nodes and the measurement duration of a single radioactivity measurement, to obtain the corrected second net count rate, includes: The first decay correction coefficient corresponding to the second time node is calculated based on the time interval between the first time node and the second time node and the first decay correction coefficient algorithm. The second decay correction coefficient corresponding to the second time node is calculated based on the measurement duration of a single radioactivity measurement and the second decay correction coefficient algorithm. The second net count rate is decay-corrected based on the first decay correction coefficient and the second decay correction coefficient corresponding to the second time node to obtain the corrected second net count rate.

[0011] In one embodiment of this application, determining the thickness reduction of the device wall in the target region based on a preset calibration correspondence, a corrected first net count rate, and a corrected second net count rate includes: The normalized net count rate is determined based on the corrected first net count rate and the corrected second net count rate. The average thickness of the device wall in the target region corresponding to the normalized net count rate is determined from the calibration correspondence. Based on the initial thickness and the average thickness of the device wall in the target area, the thickness reduction amount of the device wall in the target area is determined.

[0012] In one embodiment of this application, before determining the thickness reduction of the device wall in the target region based on a preset calibration correspondence, a corrected first net count rate, and a corrected second net count rate, the method further includes: Based on the geometric model of the liquid metal reactor device, during the simulation of the corrosion and thinning of the device wall, the actual spectral density of the tracer nuclide is collected by a gamma detector under different actual wall thicknesses; wherein, the geometric model is constructed by the user according to the device structure and material parameters of the liquid metal reactor device; Based on the initial spectral density corresponding to the initial thickness of the device wall and the actual spectral densities corresponding to each actual thickness, a normalized spectral density-thickness correspondence is constructed; the normalized spectral density is the ratio of each actual spectral density to the initial spectral density. The correspondence between the normalized spectral density and the thickness is determined as the calibration correspondence.

[0013] Secondly, embodiments of this application provide a corrosion monitoring device, the device comprising: A gamma detector includes a probe structure and a signal processing module connected to the probe structure. The gamma detector is used to measure the radioactivity of a tracer nuclide in the same target area at multiple time points in a corrosive environment where a liquid metal reactor is filled with liquid metal, obtaining the net count rate of the tracer nuclide at each time point. The target area is the portion of the reactor wall containing the tracer nuclide. The net count rate is used to determine the amount of wall thinning in the target area. A collimation shielding assembly surrounds the probe structure, and the collimation shielding assembly has a collimation hole facing the device wall; the probe structure is used to receive radiation from tracer nuclides through the collimation hole; A heat insulation component is disposed between the collimation shielding component and the device wall.

[0014] In one embodiment of this application, the probe structure includes: Base; High-purity germanium crystals; A cup body, disposed on the base, is used to hold the high-purity germanium crystal; An outer end cap is provided at the open end of the cup body to form a sealed internal cavity with the cup body and to ensure that radiation rays can enter the internal cavity.

[0015] In one embodiment of this application, the collimation shielding component is made of lead, and the base, the cup body, and the outer end cap are made of aluminum.

[0016] This application provides a corrosion monitoring method and device for a liquid metal reactor device. In a corrosive environment created by liquid metal filling the reactor, the radioactivity of tracer nuclides in the same target area can be measured at different time points using a pre-set gamma detector to obtain the net count rate of the tracer nuclides at each time point. Due to the radioactive decay effect of the tracer nuclides, decay corrections can be applied to the two net count rates based on the time interval between two time points and the measurement duration of a single measurement. Based on the ratio of the two decay-corrected net count rates, combined with a pre-set calibration correspondence, the ratio of the device wall thickness at the two time points can be obtained. Using the thickness of the device wall at one of the time points as a benchmark, the amount of wall thickness reduction in the target area within the time interval between the two time points can be obtained. Through the above implementation, the corrosion of the reactor wall in a liquid metal reactor device filled with liquid metal can be monitored and analyzed under normal operating conditions. Compared to the original method of sampling and analysis after operation, this method can obtain the corrosion status of the device wall in real time, improving the lag problem of the original method. It enables long-term, high-precision, and safe corrosion monitoring, and also provides convenience for maintenance during nuclear reactor operation. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic flowchart of a corrosion monitoring method for a liquid metal reactor device provided in one embodiment of this application; Figure 2 This is a correspondence between normalized spectral density and thickness provided in one embodiment of this application; Figure 3 This is a schematic diagram of the structure of a corrosion monitoring device provided in one embodiment of this application; Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application; Appendix Figure 3 middle: 1: Liquid metal; 2: Target area; 3: Device wall; 4: Heat insulation component; 5: Collimation shielding component; 6: Collimation hole; 7: High-purity germanium crystal; 8: Cup body; 9: Outer end cap; 10: Base. Detailed Implementation

[0019] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0020] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0021] To address the problems of the prior art, this application provides a corrosion monitoring method and a corrosion monitoring device for a liquid metal reactor. The corrosion monitoring method for a liquid metal reactor provided in this application is described below.

[0022] Figure 1 A schematic flowchart of a corrosion monitoring method for a liquid metal reactor device according to an embodiment of this application is shown. Figure 1 As shown in the embodiment of this application, the corrosion monitoring method for a liquid metal reactor device is applied to a corrosion monitoring device and includes the following steps 101-104, wherein: Step 101: In a corrosive environment where the liquid metal reactor device is filled with liquid metal, the radioactivity of the tracer nuclide is measured at the same target area at multiple time points using a gamma detector to obtain the net count rate of the tracer nuclide at each time point; wherein, the target area is the part of the device wall of the liquid metal reactor device containing the tracer nuclide.

[0023] In nuclear reactor installations, liquid metal reactor installations (hereinafter referred to as liquid metal reactor installations) can be used to store liquid metal at higher temperatures, and the liquid metal can be used as a coolant in the primary loop of the nuclear reactor.

[0024] When a liquid metal reactor is filled with and sealed with liquid metal, the reactor needs to be heated to maintain a high-temperature environment in order to keep it liquid. This high-temperature environment exposes the reactor to corrosion. To monitor corrosion, the reactor walls can be specially treated to contain tracer nuclides, allowing corrosion monitoring through the tracking of these nuclides.

[0025] The methods for adding tracer nuclides to the reactor wall can include, but are not limited to, the following: adding tracer nuclides during the smelting of the liquid metal reactor; activating the reactor wall through irradiation to make a localized area of ​​the reactor wall carry tracer nuclides; adding tracer nuclides to a localized coating of the reactor wall, or other activation / marking methods that meet safety and compliance requirements. In addition, the reactor wall of a liquid metal reactor can be composed of multiple welded parts. During the smelting of one part, a radioactive tracer nuclide can be added during the smelting process, and then this part of the material is welded to another part of the material without the added tracer nuclide to form the reactor wall. That is, any method can be used to make a localized area of ​​the reactor wall carry a radioactive tracer nuclide, and this tracer nuclide must satisfy the requirements of being usable as a tracer, measurable by gamma spectroscopy, related to the reactor wall, or able to be introduced into the reactor wall.

[0026] A gamma detector is installed on the outside of the liquid metal reactor device. By pointing the gamma detector at a specific area, the energy spectrum of the tracer nuclide in that area can be measured to determine the radioactivity of the tracer nuclide.

[0027] Understandably, to monitor and analyze corrosion in specific areas of a liquid metal reactor, energy spectrum measurements can be performed on the same target area on the reactor wall using a gamma detector at multiple different time points. Based on the measurement results obtained from the gamma detector's energy spectrum measurements of the target area at each time point, the net count rate of the tracer nuclide at each time point can be calculated and analyzed.

[0028] The net count rate mentioned above refers to the effective count rate generated solely by radioactive radiation emitted by tracer nuclides dissolved in the walls of the liquid metal reactor device, after deducting the background count rate from the total count rate measured by the gamma detector. The background count rate, on the other hand, refers to the count rate measured by the gamma detector when the device walls do not contain tracer nuclides or do not meet the conditions for tracer nuclide emission.

[0029] Understandably, the selection of tracer nuclides can be based on several factors, including the composition of the liquid metal reactor device wall, the measurability of characteristic gamma rays, and whether the half-life matches the experimental duration. For example, Fe, Cr, Co, and Mn will be used as examples below.

[0030] Fe is an important component of alloy materials, and its stable isotope is Fe-56. It also has a radioactive isotope, Fe-59, which has characteristic gamma rays of 1099.245 keV and 1291.59 keV, and a half-life of 44.49 days. Cr is an important component of corrosion-resistant alloys. Its stable isotope is Cr-52, and it has a radioactive isotope Cr-51. Its characteristic gamma ray energy is 320 keV, and its half-life is 27.7 days. Co is a common base or additive element in alloy materials. Its stable isotope is Co-59, and it has radioactive isotopes Co-56 (characteristic gamma-ray energies of 846.77 keV, 1238.29 keV, etc., with a half-life of 77.24 days), Co-57 (characteristic gamma-ray energies of 122.06 keV, 136.47 keV, etc., with a half-life of 271.74 days), and Co-58 (characteristic gamma-ray energy of 810.76 keV, with a half-life of 70.86 days). Mn is a common additive element in alloy materials. Its stable isotope is Mn-55, which has radioactive isotopes Mn-52 (characteristic gamma-ray energies of 1434.09 keV, 935.54 keV, etc., with a half-life of 5.591 days) and Mn-54 (characteristic gamma-ray energies of 834.85 keV, etc., with a half-life of 312.2 days).

[0031] In a liquid metal reactor facility used for filling liquid metal, the radioactive isotopes of all the aforementioned elements can be used as tracer nuclides. Furthermore, further selection can be made based on the introduction conditions of each radionuclide and the duration of the tracer activity.

[0032] As an example, the tracer nuclide mentioned above can be Cr-51, and its corresponding reaction channel can be Cr-52(p,n+p)Cr-51 or Cr-52(n,2n)Cr-51.

[0033] In an optional embodiment, the duration for monitoring the corrosion of the liquid metal reactor device using the above-described method can be set to 200 days. In this case, the device wall can be made into a circular sheet with a thickness of 0.3 mm and a diameter of 13.4 mm, and then irradiated with neutrons. The irradiation area should be directly facing the center of the material and uniformly cover the entire sample sheet. Under neutron irradiation of approximately 14 MeV, Cr-51, Co-57, and Co-58 are generated in the sample. After the sample is cooled for 1 to 2 days, and most of the short-lived nuclides have decayed, it can be used for subsequent experiments.

[0034] The gamma detector can be selected based on measurement requirements. For example, choosing a high-purity germanium (HPGe) detector can achieve high energy resolution, while choosing a sodium iodide (NaI) detector can achieve high detection efficiency and simplify maintenance. In addition, other gamma-ray detectors can be selected based on the composition of the device walls and the liquid metal; no restrictions are placed here.

[0035] Step 102: Based on the time interval between the first time node and the second time node and the measurement duration of a single radioactivity measurement, the first net count rate corresponding to the first time node is corrected to obtain the corrected first net count rate.

[0036] After obtaining the net count rate of the tracer nuclide at different time points, due to the radioactive decay effect of the tracer nuclide, it is necessary to perform decay correction on the net count rate at different time points.

[0037] Taking decay correction at the first and second time points out of multiple time points as an example, based on the time interval between the first and second time points and the measurement duration of a single radioactivity measurement by the gamma detector, the first net count rate corresponding to the first time point can be corrected using a preset decay correction algorithm to obtain the corrected first net count rate.

[0038] Step 103: Based on the time interval between the first time node and the second time node and the measurement duration of a single radioactivity measurement, the second net count rate corresponding to the second time node is decay-corrected to obtain the corrected second net count rate.

[0039] In this embodiment, decay correction is performed on the first and second time nodes among multiple time nodes as an example. Based on the time interval between the first and second time nodes and the measurement duration of a single radioactivity measurement by the gamma detector, a preset decay correction algorithm can be used to correct the second net count rate corresponding to the second time node to obtain the corrected second net count rate.

[0040] Step 104: Based on the preset calibration correspondence, the corrected first net count rate, and the corrected second net count rate, determine the thickness reduction of the device wall in the target area; wherein, the calibration correspondence is the correspondence between the ratio of net count rates and the thickness.

[0041] In this embodiment, after obtaining the corrected first net count rate and the corrected second net count rate, the amount of thickness reduction of the device wall in the target area can be determined based on the pre-acquired calibration correspondence.

[0042] The aforementioned calibration correspondence represents the relationship between the ratio of net count rates and thickness. Based on the corrected first and second net count rates, the ratio between them can be calculated. From this ratio, the corresponding thickness ratio can be obtained from the calibration correspondence. This thickness ratio is the ratio of the device wall thickness at the first and second time nodes, respectively. Using the device wall thickness at the first time node as a benchmark, the difference between the device wall thickness at the second time node and the thickness at the second time node represents the thickness reduction of the device wall in the target area.

[0043] In this embodiment, under the corrosive environment formed by the liquid metal reactor device filled with liquid metal, the radioactivity of tracer nuclides in the same target area can be measured at different time points using a preset gamma detector to obtain the net count rate of tracer nuclides at each time point. Since tracer nuclides exhibit radioactive decay effects, decay corrections can be applied to the two net count rates based on the time interval between two time points and the measurement duration of a single measurement. Based on the ratio of the two decay-corrected net count rates, combined with a preset calibration correspondence, the ratio of the device wall thickness at the two time points can be obtained. Using the device wall thickness at one of the time points as a benchmark, the amount of thickness reduction of the device wall in the target area within the time interval between the two time points can be obtained. Through the above implementation method, the corrosion of the device wall of a liquid metal reactor device filled with liquid metal can be monitored and analyzed under normal nuclear reactor operation. Compared to the original method of sampling and analysis after operation, this method can monitor the corrosion of the liquid metal reactor wall during normal operation of the nuclear reactor. It improves the lag problem of the original sampling and analysis method after operation, realizes long-term, high-precision and safe corrosion monitoring, and can also provide convenience for maintenance during nuclear reactor operation.

[0044] It should be noted that the above embodiments only illustrate corrosion monitoring of a single target area on the device wall. This embodiment can be achieved by using a single gamma detector to perform measurements at different time points. If measurements need to be taken at multiple locations on the device wall, measurements can be performed at multiple locations by moving a single gamma detector, or multiple corresponding gamma detectors can be deployed at multiple locations for measurement.

[0045] After obtaining the corrosion thinning analysis results for a certain region of the device wall using the above-described implementation method, the remaining wall thickness and thinning rate of that region can be compared with the design-allowed thinning threshold and the expected corrosion thinning rate to determine the degree of deviation, thereby assessing the structural reliability of the device wall material. When the actual corrosion thinning rate is significantly higher than expected, it indicates that the corrosion protection measures within the device may be abnormal, requiring further investigation or a shortened operating cycle. When the remaining wall thickness is lower than the design-allowed thinning threshold, it indicates that the remaining thickness of the device wall material no longer meets the preset integrity requirements, necessitating shutdown for inspection or repair / replacement. It is understood that, in addition to the methods listed above, relevant personnel can also take appropriate actions based on the corrosion thinning analysis results, combined with the design specifications and maintenance conditions of the liquid metal reactor device; no restrictions are imposed here.

[0046] In one embodiment of this application, the step of measuring the radioactivity of a tracer nuclide in the same target area at multiple time points using a gamma detector to obtain the net count rate of the tracer nuclide at each time point includes: At each time point, the gamma spectrum of the target region is collected by a gamma detector, and the characteristic gamma-ray peaks of the tracer nuclide are extracted from the gamma spectrum to determine the total count of the tracer nuclide. The net count rate of the tracer nuclide is calculated based on the total count of the tracer nuclide, the pre-acquired background count, and the corresponding measurement time.

[0047] In this embodiment, in the corrosive environment of the liquid metal reactor device filled with liquid metal, the gamma spectrum of the same target area can be collected at different time points by a gamma detector, and the characteristic gamma peak of the tracer nuclide can be extracted from the gamma spectrum. Based on the characteristic gamma peak, the total count of the tracer nuclide can be obtained.

[0048] Based on the total count of the tracer nuclide and the measurement duration of the gamma detector, the total count rate of the tracer nuclide can be calculated. Combined with the pre-acquired background count (i.e., the pre-measured background count) and the corresponding measurement time, the corresponding background count rate can be calculated. The difference between the total count rate and the background count rate can be used to obtain the net count rate of the tracer nuclide.

[0049] The aforementioned background count refers to the count of all radiation signals unrelated to the tracer nuclide obtained by the gamma detector measuring the target area within the corresponding measurement time. For example, this part of the radiation signal can be the natural background radiation of the current environment (such as cosmic rays, natural radioactivity of soil building materials, etc.), detector noise, electronic baseline interference, stray gamma radiation generated by the cavity base, cup, and shielding structure of the gamma detector itself, as well as irrelevant radiation interference from other surrounding equipment, etc., without limitation.

[0050] The aforementioned background count can be obtained by measuring the radioactivity of a target area of ​​a liquid metal reactor device without activated tracer nuclides under the same test environment, determining a stable background count based on the collected energy spectrum data, and determining the corresponding background count rate based on the measurement duration.

[0051] It is understood that the above-described implementation method can achieve diagnostic monitoring of corrosion thinning. By measuring the gamma spectrum of the target area of ​​the device wall at regular intervals, the change in the count rate of characteristic gamma rays over time can be obtained. With the detection efficiency remaining constant (or with corrections made for changes in detection efficiency due to factors such as location), and with appropriate decay corrections applied to the count rate, the actual decrease in the count rate is only related to the reduction in the total amount of tracer nuclides and the weakening of the self-shielding effect caused by the thinning of the device wall. Based on this, the amount of local thinning of the device wall can be calculated.

[0052] As an example, in order to reduce the interference of the tracer nuclide background in the lead-bismuth bulk phase on the near-wall thinning judgment, low-energy gamma rays can be selected to enhance the sensitivity of near-wall region measurements and reduce the contribution of impurity nuclides in the distant liquid metal bulk phase, in cases where radionuclide redeposition may occur on the device wall surface.

[0053] In one embodiment of this application, calculating the net count rate corresponding to the tracer nuclide based on the total count of the tracer nuclide, the pre-acquired background count, and the corresponding measurement time includes: The total count of the tracer nuclides is divided by the corresponding measurement duration to obtain the total count rate of the tracer nuclides; Divide the pre-acquired background count by the corresponding measurement duration to obtain the background count rate; The net count rate corresponding to the tracer nuclide is obtained by subtracting the background count rate from the total count rate of the tracer nuclide.

[0054] In this embodiment, the total count of tracer nuclides is divided by the corresponding measurement duration to obtain the total count rate of tracer nuclides, and the corresponding measurement duration is the measurement duration of the gamma detector in this case; the pre-acquired background count is divided by the corresponding measurement duration to obtain the background count rate; further, the total count rate of tracer nuclides is subtracted from the background count rate to obtain the net count rate of the tracer nuclides.

[0055] In one embodiment of this application, the first time point is the initial moment when the liquid metal reactor device starts operating; The step of correcting the first net count rate corresponding to the first time node based on the time interval between the first and second time nodes and the measurement duration of a single radioactivity measurement, to obtain the corrected first net count rate, includes: The first decay correction coefficient corresponding to the first time node is calculated based on the time interval between the first time node and the second time node and the first decay correction coefficient algorithm. The second decay correction coefficient corresponding to the first time node is calculated based on the measurement duration of a single radioactivity measurement and the second decay correction coefficient algorithm. The first net count rate is decay-corrected based on the first decay correction coefficient and the second decay correction coefficient corresponding to the first time node to obtain the corrected first net count rate.

[0056] In this embodiment, the first time point can be the initial moment when the liquid metal reactor device starts to operate. At this time, it can be approximately assumed that the liquid metal has not yet corroded the device wall of the liquid metal reactor device. The thickness of the device wall at this time can be obtained by measurement and used as the initial thickness.

[0057] Since the first time point is the initial moment, by the second time point, the liquid metal has already corroded the reactor wall for a certain period of time. Therefore, the thickness of the reactor wall has decreased to some extent by the second time point.

[0058] Based on the time interval between the first time node and the second time node, the first decay correction coefficient corresponding to the first time node can be calculated according to the first decay coefficient correction algorithm.

[0059] Based on the measurement duration of a single radioactivity measurement, the second decay correction coefficient corresponding to the first time node can be calculated according to the second decay coefficient correction algorithm.

[0060] Understandably, if the duration of a single measurement by the gamma detector remains constant, the first and second time nodes will have the same second decay coefficient. If the duration of a single measurement by the gamma detector may differ in different detection processes, then the second decay correction coefficient corresponding to the first time node needs to be calculated according to the second decay coefficient correction algorithm. Furthermore, the first net count rate is decay corrected based on the first and second decay correction coefficients corresponding to the first time node to obtain the corrected first net count rate.

[0061] In one embodiment of this application, the first time point is the initial moment when the liquid metal reactor device starts operating; The step of performing decay correction on the second net count rate corresponding to the second time node based on the time interval between the first and second time nodes and the measurement duration of a single radioactivity measurement, to obtain the corrected second net count rate, includes: The first decay correction coefficient corresponding to the second time node is calculated based on the time interval between the first time node and the second time node and the first decay correction coefficient algorithm. The second decay correction coefficient corresponding to the second time node is calculated based on the measurement duration of a single radioactivity measurement and the second decay correction coefficient algorithm. The second net count rate is decay-corrected based on the first decay correction coefficient and the second decay correction coefficient corresponding to the second time node to obtain the corrected second net count rate.

[0062] In this embodiment, the first time point can be the initial moment when the liquid metal reactor device starts to operate. At this time, it can be approximately assumed that the liquid metal has not yet corroded the device wall of the liquid metal reactor device. The thickness of the device wall at this time can be obtained by measurement and used as the initial thickness.

[0063] Since the first time point is the initial moment, by the second time point, the liquid metal has already corroded the reactor wall for a certain period of time. Therefore, the thickness of the reactor wall has decreased to some extent by the second time point.

[0064] Based on the time interval between the first and second time nodes, the first decay correction coefficient corresponding to the second time node can be calculated according to the first decay coefficient correction algorithm.

[0065] Based on the measurement duration of a single radioactivity measurement, the second decay correction coefficient corresponding to the second time node can be calculated according to the second decay coefficient correction algorithm.

[0066] Understandably, if the duration of a single measurement by the gamma detector remains constant, the first and second time nodes will have the same second decay coefficient. If the duration of a single measurement by the gamma detector may differ in different detection processes, then the second decay correction coefficient corresponding to the second time node needs to be calculated according to the second decay coefficient correction algorithm. Furthermore, the second net count rate is decay corrected based on the first and second decay correction coefficients corresponding to the second time node to obtain the corrected second net count rate.

[0067] In one embodiment of this application, the first decay correction coefficient algorithm and the second decay correction coefficient algorithm further include the decay coefficient of the tracer nuclide.

[0068] In this embodiment, the radioactive decay effects differ for different tracer nuclides. Therefore, in the calculation of decay correction, both the first and second decay correction coefficient algorithms must include the decay coefficient of the tracer nuclide in their calculation formulas, so as to enable accurate decay coefficient correction based on the selected tracer nuclide.

[0069] As an example, the algorithm for the first decay correction coefficient described above may include the following formula: (1); (2); in, This is the first decay correction factor. The decay coefficient of the tracer nuclide, Let n be the start time of the nth measurement process. At the initial moment, This refers to the time interval between two measurements.

[0070] The algorithm for the second decay correction coefficient mentioned above can include the following formula: (3); (4); in, This is the second decay correction factor. The decay coefficient of a tracer nuclide can be obtained by consulting relevant materials. Let n be the end time of the nth measurement process. Let n be the start time of the nth measurement process. This refers to the measurement duration of a single measurement.

[0071] Based on the first and second decay correction coefficients mentioned above, the decay correction formula for the net count rate includes: (5); in, The net count rate without decay correction is obtained from the nth measurement. and These are the first decay correction coefficient and the second decay correction coefficient for the nth measurement process, i.e., the second time node.

[0072] It is understandable that, since the first time point is the initial moment, the initial moment... The value is 0, meaning the corresponding first decay correction factor is 1.

[0073] In the above embodiments, since the first time node is always the initial time, after the first net count rate is decayed, the decay correction can be removed in subsequent multiple measurements, and the decayed first net count rate can be obtained directly.

[0074] In one alternative implementation, the decay-corrected first net count rate can be The decay-corrected second net count rate can be At this point, the ratio of the net counting rate is: (6); The ratio of the net count rate calculated above can be used as the normalized net count rate. The thickness corresponding to the normalized net count rate can be obtained from the preset calibration correspondence, which is the average thickness of the device wall at the second time node.

[0075] In one embodiment of this application, determining the thickness reduction of the device wall in the target region based on a preset calibration correspondence, a corrected first net count rate, and a corrected second net count rate includes: The normalized net count rate is determined based on the corrected first net count rate and the corrected second net count rate. The average thickness of the device wall in the target region corresponding to the normalized net count rate is determined from the calibration correspondence. Based on the initial thickness and the average thickness of the device wall in the target area, the thickness reduction amount of the device wall in the target area is determined.

[0076] In this embodiment, the normalized net count rate can be obtained by dividing the first net count rate and the second net count rate, respectively.

[0077] In the preset calibration correspondence, the corresponding thickness ratio can be determined based on the normalized net count rate. This thickness ratio is the ratio of the thickness of the device wall at the second time node to the thickness of the device wall at the first time node. Since the initial thickness of the device wall can be obtained by measuring or querying device parameters, the average thickness of the device wall in the target area measured at the second time node can be determined based on this thickness ratio and the initial thickness.

[0078] Based on the initial thickness and average thickness of the device wall in the target area, the difference between the initial thickness and the average thickness can be calculated to obtain the thickness reduction of the device wall in the target area.

[0079] In one embodiment of this application, before determining the thickness reduction of the device wall in the target region based on a preset calibration correspondence, a corrected first net count rate, and a corrected second net count rate, the method further includes: Based on the geometric model of the liquid metal reactor device, during the simulation of the corrosion and thinning of the device wall, the actual spectral density of the tracer nuclide is collected by a gamma detector under different actual wall thicknesses; wherein, the geometric model is constructed by the user according to the device structure and material parameters of the liquid metal reactor device; Based on the initial spectral density corresponding to the initial thickness of the device wall and the actual spectral densities corresponding to each actual thickness, a normalized spectral density-thickness correspondence is constructed; the normalized spectral density is the ratio of each actual spectral density to the initial spectral density. The correspondence between the normalized spectral density and the thickness is determined as the calibration correspondence.

[0080] In this embodiment, before the liquid metal reactor device is filled with liquid metal and operates normally, the calibration correspondence can be determined by simulation.

[0081] Since the structure and material parameters of the liquid metal reactor device are known data, users can construct a geometric model based on the structure and material parameters of the liquid metal reactor device.

[0082] Based on the geometric model of a liquid metal reactor device, during the simulation of the wall corrosion and thinning process of the reactor device, the actual spectral density of the tracer nuclide is collected by a gamma detector at different actual wall thicknesses. Specifically, through a preset simulation algorithm, the simulation is performed to simulate the corrosion of the reactor device wall by liquid metal after the tracer nuclide is injected. During the simulated wall corrosion and thinning process, the actual wall thickness will gradually decrease due to corrosion. Multiple time points can be selected throughout the simulation process, corresponding to different remaining actual wall thicknesses due to corrosion. At each time point, the motion of the tracer nuclide's radiating particles can be simulated. A virtual gamma detector can be set within a preset range of the geometric model to collect the actual spectral density of the tracer nuclide detected by the gamma detector during radioactivity measurement.

[0083] Since the first time point is the initial moment among multiple time points, the initial spectral density obtained by the gamma detector from the tracer nuclide at the initial thickness of the device wall at the initial moment can be determined by the simulation algorithm.

[0084] At other time points, the gamma detector measures the radioactivity of the tracer nuclides, and can obtain the actual spectral density corresponding to the actual thickness of the device wall at different time points.

[0085] For the actual spectral density at each time point, i.e., the actual spectral density corresponding to each actual thickness, the actual spectral density can be divided by the initial spectral density to obtain the normalized spectral density for each actual thickness. That is, the normalized spectral density is the ratio of each actual spectral density to the initial spectral density.

[0086] Since the actual thickness of the device wall and the normalized spectral density are known, a correspondence between the normalized spectral density and the thickness can be constructed.

[0087] Under the same equipment and detection conditions, it is understandable that the spectral density of the tracer nuclide obtained through simulation calculation is directly proportional to the net count rate of the characteristic peaks of the radioactive rays of that tracer nuclide measured experimentally. Therefore, by normalizing the spectral density obtained at two different time points, the influence of fixed proportionality coefficients such as detector efficiency can be eliminated. At this point, the relationship between the normalized spectral density and thickness can be determined as the relationship between the ratio of net count rate and thickness.

[0088] Please refer to Figure 2 , Figure 2 The relationship between the normalized spectral density obtained using the above method and the wall thickness of the device is shown. For example... Figure 2As shown, at the initial moment, the wall thickness of the device is 1.0 cm, corresponding to a normalized spectral density of 1.0 au. As the liquid metal corrodes the device wall, the wall thickness gradually decreases. That is, the normalized spectral density of the tracer nuclide is positively correlated with the wall thickness.

[0089] As an example, the above-mentioned method aims to monitor the degree of corrosion thinning of the device wall by uniformly distributing tracer nuclides, such as Cr-51, in a portion of the device wall through melting or neutron irradiation.

[0090] During the corrosion of the reactor wall by liquid metal in a liquid metal reactor, the corrosion thinning of the reactor wall can be monitored by collecting the gamma spectrum of the target area and extracting the net count rate of the 320 keV characteristic gamma rays of Cr-51.

[0091] Understandably, before conducting corrosion monitoring, a calibration curve of "wall thickness - net count rate" for the structure of the system under study (including liquid metal medium, structural materials of liquid metal reactor device, air, collimation shielding components, and gamma detector) can be established in advance using Monte Carlo simulation algorithms.

[0092] During the measurement, after measuring the net count rate and correcting for its decay, the remaining wall thickness of the device wall at the current moment can be found based on the calibration curve mentioned above. Alternatively, the amount of thinning can be obtained by subtracting the remaining wall thickness from the wall thickness at the initial moment.

[0093] Figure 3 A schematic diagram of the corrosion monitoring device provided in an embodiment of this application is shown. This corrosion monitoring device can be used to perform the corrosion monitoring method for liquid metal reactor devices described in the above embodiments. Figure 3 As shown, the corrosion monitoring device includes a gamma detector, a collimation shielding assembly 5, and a heat insulation assembly 4.

[0094] A gamma detector includes a probe structure and a signal processing module connected to the probe structure. The gamma detector is used to measure the radioactivity of a tracer nuclide in the same target area at multiple time points in a corrosive environment where a liquid metal reactor is filled with liquid metal, obtaining the net count rate of the tracer nuclide at each time point. The target area is the portion of the reactor wall containing the tracer nuclide. The net count rate is used to determine the amount of wall thinning in the target area. A collimation shielding assembly surrounds the probe structure, and the collimation shielding assembly has a collimation hole facing the device wall; the probe structure is used to receive radiation from tracer nuclides through the collimation hole; A heat insulation component is disposed between the collimation shielding component and the device wall.

[0095] In this embodiment, the liquid metal reactor device contains liquid metal 1. The gamma detector may include a probe structure and a signal processing module connected to the probe structure. The gamma detector can measure the radioactivity of tracer nuclides on the device wall 3 of the liquid metal reactor device. For example, the scintillation crystal disposed on the probe structure may be high-purity germanium or sodium iodide, etc. The scintillation crystal can generate a weak photocurrent signal based on the received radiation rays and transmit it to the signal processing module electrically connected to the probe structure. The signal processing module can perform signal amplification, signal filtering, analog-to-digital conversion, etc. on the photocurrent signal, and analyze and calculate the converted digital signal to obtain the net count rate corresponding to the tracer nuclide.

[0096] The gamma detector is used to measure the radioactivity of tracer nuclides in the same target area at multiple time points in a corrosive environment where liquid metal is filled in a liquid metal reactor device, and to obtain the net count rate of the tracer nuclide at each time point; wherein, the target area is the part of the device wall of the liquid metal reactor device containing the tracer nuclide.

[0097] The net count rate is used to determine the amount of thickness reduction of the device wall in the target area. Specifically, based on the time interval between the first and second time nodes and the measurement duration of a single radioactivity measurement, the first net count rate corresponding to the first time node is corrected to obtain the corrected first net count rate; based on the time interval between the first and second time nodes and the measurement duration of a single radioactivity measurement, the second net count rate corresponding to the second time node is decay corrected to obtain the corrected second net count rate; based on the preset calibration correspondence, the corrected first net count rate, and the corrected second net count rate, the amount of thickness reduction of the device wall in the target area is determined; wherein, the calibration correspondence is the correspondence between the ratio of net count rates and the thickness.

[0098] The collimation shielding assembly 5 is arranged around the probe structure, or at least partially around it. This assembly has a collimation hole 6 facing the device wall 3. During gamma detector measurements, the collimation shielding assembly 5 can be placed in front of the probe structure, allowing the scintillation crystal on the probe structure to receive radiation from tracer nuclides within the field of view only through the collimation hole 6. This enables measurement of the target area 2 (such as cold spots, bends, or specific pipe sections) of the designated liquid metal reactor device. The aperture and length of the collimation hole 6 can be set according to the actual requirements of spatial resolution and count rate.

[0099] The aforementioned collimation shielding component 5 can be a shielding body made of lead (or high-density materials such as tungsten). This shielding body can cover the probe structure of the gamma detector. The shielding body is provided with a collimation hole 6 or a slit or other collimation structure to limit the detection area of ​​the probe structure, thereby reducing the interference of radiation generated by other non-target areas on the detection results.

[0100] It should be noted that, in order to prevent the probe structure of the gamma detector from receiving radiation for a long time when no measurement is being performed, the collimation shielding component 5 can be configured to be shieldable or movable, so that the probe structure will not receive radiation through the collimation hole 6 when the gamma detector is not performing measurements.

[0101] It is understood that the above-mentioned shieldable type refers to the fact that the collimation shielding assembly 5 is provided with a shielding plate for shielding the collimation hole 6. The shielding plate can be moved to open and block the collimation hole 6. When the gamma detector is not running, the collimation hole 6 can be blocked by moving the shielding plate, thereby blocking the passage between the collimation hole 6 and the gamma detector.

[0102] The term "movable" refers to the ability to move a portion of the collimation aperture 6 within the collimation shielding assembly 5. When the gamma detector is not in operation, the collimation aperture 6 can be moved away from the device wall 3 of the liquid metal reactor by moving a portion of the collimation shielding assembly 5 or by moving the collimation shielding assembly 5 itself, thereby preventing radiation rays from reaching the probe structure through the collimation aperture 6.

[0103] The aforementioned heat insulation component 4 can be disposed between the collimation shielding component 5 and the device wall 3. Since the liquid metal in the liquid metal reactor device needs to remain liquid in a high-temperature environment to maintain its liquid state, this high-temperature environment may have a thermal impact on the collimation shielding component 5 or the gamma detector. By setting the heat insulation component 4, a certain distance can be maintained between the collimation shielding component 5 and the liquid metal reactor device, thereby achieving a heat insulation function, preventing the high-temperature outer wall of the device wall 3 from melting the collimation shielding component 5, and improving the service life of the collimation shielding component 5 and the gamma detector.

[0104] As an example, the heat insulation component 4 can be a heat insulation pad, such as made of aluminum silicate, or a shielding plate made of other high-temperature resistant materials (such as tungsten), etc., without limitation. The distance between the collimating shielding component 5 and the liquid metal reactor device separated by the heat insulation pad can be determined based on the penetrating power of the characteristic gamma rays of the tracer nuclide. For example, by experimentally measuring the attenuation curve of the characteristic gamma rays of the selected tracer nuclide, the distance between the collimating shielding component 5 and the liquid metal reactor device can be determined based on the experimental measurement results. Alternatively, the distance can also be determined by simulation calculation, without limitation.

[0105] In one optional embodiment, the liquid metal is a high-temperature liquid lead-bismuth eutectic alloy, the device wall 3 of the liquid metal reactor is an iron-based alloy (e.g., 316L stainless steel), and the tracer nuclide is Cr-51. A geometric and material model including the gamma detector, collimation shielding assembly 5, the device wall 3 under test, and the lead-bismuth medium is established using a Monte Carlo simulation program (e.g., MCNP). Based on this geometric model, the full-energy peak detection efficiency ε(d) of the characteristic gamma rays (320 keV) of Cr-51 at different detection distances d is calculated.

[0106] It is understandable that the above detection efficiency can be measured by comparison experiments between the reference device and the sample, or by simulation calculation, and no limitation is made here.

[0107] Given the Cr-51 activity A, characteristic gamma-ray emission probability (branching ratio) P in target region 2, and the expected measurement live time t, the expected net count N(d) at a detection distance d can be calculated: (7); According to the above formula, by combining parameters such as the background count of the device wall 3 and the expected measurement time of the gamma detector, a suitable detection distance can be selected so that the uncertainty of the measurement result is better than the preset threshold (e.g., 5%).

[0108] In this embodiment, by setting up the collimation shielding component 5, the probe structure of the gamma detector can receive the radiation rays of the tracer nuclide through the collimation hole 6 on the collimation shielding component 5. The weak photocurrent signal generated by the radiation rays can be analyzed and processed by the signal processing module to achieve the measurement of the radioactivity of the device wall 3 of the liquid metal reactor device. By setting up the heat insulation component 4, the high temperature of the liquid metal reactor device can also be prevented from affecting the normal operation of the collimation shielding component 5 and the gamma detector.

[0109] In one embodiment of this application, the probe structure may include a base 10, a high-purity germanium crystal 7, a cup body 8, and an outer end cap 9.

[0110] The cup body 8 can be mounted on the base 10, and the high-purity germanium crystal 7 can be contained within the cup body 8. An outer end cap 9 can be positioned at the open end of the cup body 8, forming a sealed internal cavity with the cup body 8, and the outer end cap 9 will not interfere with the normal entry of radioactive rays. That is, the radioactive rays of the tracer nuclide can enter the high-purity germanium crystal 7 through the collimating hole 6 and the outer end cap 9, causing it to generate a corresponding weak photocurrent signal.

[0111] In one embodiment of this application, the collimation shielding component 5 may be made of lead to achieve shielding against radiation. The base 10, the cup body 8, and the outer end cap 9 may be made of aluminum to reduce interference with radiation, allowing radiation to pass through the aluminum and enter the high-purity germanium crystal 7.

[0112] Figure 4 A schematic diagram of the hardware structure of the electronic device provided in an embodiment of this application is shown.

[0113] The electronic device may include a processor 401 and a memory 402 storing computer program instructions.

[0114] Specifically, the processor 401 may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0115] Memory 402 may include mass storage for data or instructions. For example, and not limitingly, memory 402 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 402 may include removable or non-removable (or fixed) media. Where appropriate, memory 402 may be internal or external to the integrated gateway disaster recovery device. In a particular embodiment, memory 402 is non-volatile solid-state memory.

[0116] Memory may include read-only memory (ROM), random access memory (RAM), disk storage media devices, optical storage media devices, flash memory devices, and electrical, optical, or other physical / tangible memory storage devices. Therefore, typically, memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to the first aspect of this disclosure.

[0117] The processor 401 implements any of the methods described above in the above embodiments by reading and executing computer program instructions stored in the memory 402.

[0118] In one example, the electronic device may also include a communication interface 403 and a bus 410. For example, Figure 4As shown, the processor 401, memory 402, and communication interface 403 are connected through bus 410 and complete communication with each other.

[0119] The communication interface 403 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of this application.

[0120] Bus 410 includes hardware, software, or both, that couples components of a method or electronic device as described above together. For example, and not as a limitation, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or combinations of two or more of these. Where appropriate, bus 410 may include one or more buses. Although specific buses are described and illustrated in embodiments of this application, any suitable bus or interconnect is contemplated herein.

[0121] Alternatively, embodiments of this application can be implemented using a computer storage medium. This computer storage medium stores computer program instructions; when these computer program instructions are executed by a processor, they implement any of the corrosion monitoring methods for liquid metal reactor devices described in the above embodiments.

[0122] Alternatively, this application embodiment can provide a computer program product for implementation, wherein when the instructions in the computer program product are executed by the processor of an electronic device, the electronic device implements any of the corrosion monitoring methods for liquid metal reactor devices in the above embodiments.

[0123] It should be clarified that this application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described as examples. However, the method process of this application is not limited to the specific steps described. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application.

[0124] The functional blocks shown in the above-described structural diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0125] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0126] The aspects of this disclosure have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by special-purpose hardware performing the specified functions or actions, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0127] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application 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 this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A corrosion monitoring method for a liquid metal reactor device, characterized in that, The method includes: In a corrosive environment where a liquid metal reactor is filled with liquid metal, the radioactivity of tracer nuclides is measured at multiple time points in the same target area using a gamma detector to obtain the net count rate of the tracer nuclides at each time point; wherein, the target area is the part of the device wall of the liquid metal reactor containing the tracer nuclides. Based on the time interval between the first and second time nodes and the measurement duration of a single radioactivity measurement, the first net count rate corresponding to the first time node is corrected to obtain the corrected first net count rate. Based on the time interval between the first and second time nodes and the measurement duration of a single radioactivity measurement, the second net count rate corresponding to the second time node is decay-corrected to obtain the corrected second net count rate. Based on the preset calibration correspondence, the corrected first net count rate, and the corrected second net count rate, the thickness reduction of the device wall in the target area is determined; wherein, the calibration correspondence is the correspondence between the ratio of net count rates and the thickness.

2. The corrosion monitoring method for a liquid metal reactor device according to claim 1, characterized in that, The step of measuring the radioactivity of tracer nuclides in the same target area at multiple time points using a gamma detector to obtain the net count rate of the tracer nuclide at each time point includes: At each time point, the gamma spectrum of the target region is collected by a gamma detector, and the characteristic gamma-ray peaks of the tracer nuclide are extracted from the gamma spectrum to determine the total count of the tracer nuclide. The net count rate of the tracer nuclide is calculated based on the total count of the tracer nuclide, the pre-acquired background count, and the corresponding measurement time.

3. The corrosion monitoring method for a liquid metal reactor device according to claim 2, characterized in that, The calculation of the net count rate corresponding to the tracer nuclide based on the total count of the tracer nuclide, the pre-acquired background count, and the corresponding measurement time includes: The total count of the tracer nuclide is divided by the corresponding measurement duration to obtain the total count rate of the tracer nuclide; Divide the pre-acquired background count by the corresponding measurement duration to obtain the background count rate; The net count rate corresponding to the tracer nuclide is obtained by subtracting the background count rate from the total count rate of the tracer nuclide.

4. The corrosion monitoring method for a liquid metal reactor device according to claim 1, characterized in that, The first time point is the initial moment when the liquid metal reactor device starts operating; The step of correcting the first net count rate corresponding to the first time node based on the time interval between the first and second time nodes and the measurement duration of a single radioactivity measurement, to obtain the corrected first net count rate, includes: The first decay correction coefficient corresponding to the first time node is calculated based on the time interval between the first time node and the second time node and the first decay correction coefficient algorithm. The second decay correction coefficient corresponding to the first time node is calculated based on the measurement duration of a single radioactivity measurement and the second decay correction coefficient algorithm. The first net count rate is decay-corrected based on the first decay correction coefficient and the second decay correction coefficient corresponding to the first time node to obtain the corrected first net count rate.

5. The corrosion monitoring method for a liquid metal reactor device according to claim 4, characterized in that, The first time point is the initial moment when the liquid metal reactor device starts operating; The step of performing decay correction on the second net count rate corresponding to the second time node based on the time interval between the first and second time nodes and the measurement duration of a single radioactivity measurement, to obtain the corrected second net count rate, includes: The first decay correction coefficient corresponding to the second time node is calculated based on the time interval between the first time node and the second time node and the first decay correction coefficient algorithm. The second decay correction coefficient corresponding to the second time node is calculated based on the measurement duration of a single radioactivity measurement and the second decay correction coefficient algorithm. The second net count rate is decay-corrected based on the first decay correction coefficient and the second decay correction coefficient corresponding to the second time node to obtain the corrected second net count rate.

6. The corrosion monitoring method for a liquid metal reactor device according to claim 1, characterized in that, The determination of the thickness reduction of the device wall in the target region based on the preset calibration correspondence, the corrected first net count rate, and the corrected second net count rate includes: The normalized net count rate is determined based on the corrected first net count rate and the corrected second net count rate. The average thickness of the device wall in the target region corresponding to the normalized net count rate is determined from the calibration correspondence. Based on the initial thickness and the average thickness of the device wall in the target area, the thickness reduction amount of the device wall in the target area is determined.

7. The corrosion monitoring method for a liquid metal reactor device according to claim 1, characterized in that, Before determining the thickness reduction of the device wall in the target region based on a preset calibration correspondence, a corrected first net count rate, and a corrected second net count rate, the method further includes: Based on the geometric model of the liquid metal reactor device, during the simulation of the corrosion and thinning of the device wall, the actual spectral density of the tracer nuclide is collected by a gamma detector under different actual wall thicknesses; wherein, the geometric model is constructed by the user according to the device structure and material parameters of the liquid metal reactor device; Based on the initial spectral density corresponding to the initial thickness of the device wall and the actual spectral densities corresponding to each actual thickness, a normalized spectral density-thickness correspondence is constructed; the normalized spectral density is the ratio of each actual spectral density to the initial spectral density. The correspondence between the normalized spectral density and the thickness is determined as the calibration correspondence.

8. A corrosion monitoring device, characterized in that, The device includes: A gamma detector includes a probe structure and a signal processing module connected to the probe structure. The gamma detector is used to measure the radioactivity of a tracer nuclide in the same target area at multiple time points in a corrosive environment where a liquid metal reactor is filled with liquid metal, obtaining the net count rate of the tracer nuclide at each time point. The target area is the portion of the reactor wall containing the tracer nuclide. The net count rate is used to determine the amount of wall thinning in the target area. A collimation shielding assembly surrounds the probe structure, and the collimation shielding assembly has a collimation hole facing the device wall; the probe structure is used to receive radiation from tracer nuclides through the collimation hole; A heat insulation component is disposed between the collimation shielding component and the device wall.

9. The corrosion monitoring device according to claim 8, characterized in that, The probe structure includes: Base; High-purity germanium crystals; A cup body, disposed on the base, is used to hold the high-purity germanium crystal; An outer end cap is provided at the open end of the cup body to form a sealed internal cavity with the cup body and to ensure that radiation rays can enter the internal cavity.

10. The corrosion monitoring device according to claim 9, characterized in that, The collimation shielding component is made of lead, while the base, the cup body, and the outer end cap are made of aluminum.

Images