Method and system for testing and evaluating the radiation protection properties of concrete

Abstract

The present application belongs to the technical field of concrete radiation protection performance detection, and particularly relates to a method and system for testing and evaluating the radiation protection performance of concrete. The method comprises the following steps: using X-ray to irradiate a standard shielding element with a thickness gradient, obtaining a DR image of the standard shielding element, extracting average gray values under each gradient thickness, and constructing an average gray-equal thickness mapping model; under the same test environment, using X-ray to irradiate a concrete test piece to be tested, capturing the penetrating rays through a flat panel detector and converting them into digital electrical signals to generate a DR image of the concrete test piece to be tested; extracting the average gray value of the DR image of the concrete test piece to be tested, calculating the equivalent thickness parameter of the concrete test piece to be tested based on the average gray-equal thickness mapping model; and according to the equivalent thickness parameter, calculating the radiation shielding performance parameter of the concrete test piece to be tested to realize quantitative evaluation of the overall and local radiation protection performance of the concrete structure.

Description

Technical Field

[0001] This invention belongs to the field of concrete radiation protection performance testing technology, specifically relating to a method and system for testing and evaluating the radiation protection performance of concrete, including a workflow and post-test evaluation for determining the radiation protection performance of concrete using the penetration method. Background Technology

[0002] Currently, the penetration method is commonly used in the field of concrete radiation protection performance testing. In practice, this involves irradiating the concrete with radioactive rays and measuring the radiation dose rate before and after ray transmission using a Unidos dosimeter. The difference between the two values ​​is then used to convert the concrete thickness into an equivalent steel thickness. However, this method can only measure a single point on the concrete at a time. To obtain data on the overall radiation protection performance of the structure, numerous tests must be conducted at a large number of points, making the process cumbersome and inefficient.

[0003] In the traditional method of testing the radiation shielding performance of concrete, the Unidos dosimeter is used for single-point measurements, which suffers from low testing efficiency and long time consumption. More importantly, since actual concrete structures generally contain steel reinforcement phase, which makes a significant contribution to the overall radiation shielding performance, the traditional single-point measurement mode is difficult to effectively decouple and quantify the radiation shielding contributions of the steel reinforcement and the concrete matrix.

[0004] Therefore, how to provide an efficient and convenient overall structural radiation protection testing solution to achieve dual quantitative analysis of the overall structural performance and local characteristics is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a method and system for testing and evaluating the radiation protection performance of concrete. The aim is to reasonably distinguish and evaluate the local radiation protection performance of different material regions within concrete by introducing spatial dimension analytical capabilities, thereby achieving a dual quantitative analysis of the overall structural performance and local characteristics.

[0006] To achieve the above objectives, the present invention provides the following solution: A method for testing and evaluating the radiation protection performance of concrete, the method comprising: S1. Use X-rays to irradiate a standard shield with a thickness gradient, obtain a DR image of the standard shield, extract the average gray value under each thickness gradient, and construct an average gray value-equivalent thickness mapping model. S2. Under the same test environment as S1, X-rays are used to irradiate the concrete specimen to be tested. The penetrating rays are captured by a flat panel detector and converted into digital electrical signals to generate DR images of the concrete specimen to be tested. S3. Extract the average gray value of the DR image of the concrete specimen to be tested, and calculate the equivalent thickness parameter of the concrete specimen to be tested based on the average gray value-equivalent thickness mapping model. S4. Based on the equivalent thickness parameter, calculate the radiation shielding performance parameters of the concrete specimen to be tested, so as to achieve a quantitative evaluation of the overall and local radiation protection performance of the concrete structure.

[0007] Preferably, the method for extracting the average gray value under each gradient thickness in S1 and constructing the average gray value-equivalent thickness mapping model includes: The radiation dose rate before X-ray transmission and the radiation dose rate after X-ray transmission through a standard shield were measured using a Unidos dosimeter. Based on the average gray value under each gradient thickness and the radiation dose rate after X-ray transmission through a standard shield, a linear function of average gray value and radiation dose rate after transmission is established. Based on the radiation dose rate after X-ray transmission through a standard shield and the thickness of the standard shield, a radiation dose rate-thickness exponential function is established. Based on the linear function of average gray level-transmitted radiation dose rate and the exponential function of transmitted radiation dose rate-thickness, an average gray level-equivalent thickness mapping model is constructed.

[0008] Preferably, the method for establishing a radiation dose rate-thickness exponential function after X-ray transmission to a standard shield and the thickness of the standard shield includes: ; in, This represents the radiation dose rate after X-ray transmission through a standard shielding device. This represents the X-ray radiation dose rate before transmission. The linear attenuation coefficient is... For thickness.

[0009] Preferably, the method for extracting the average grayscale value of the DR image of the concrete specimen under test in step S3, and calculating the equivalent thickness parameter of the concrete specimen under test based on the average grayscale-equivalent thickness mapping model includes: By utilizing the spatial resolution characteristics of the DR image of the concrete specimen to be tested, grayscale is extracted from different regions in the DR image of the concrete specimen to be tested, so as to calculate the local equivalent thickness of the overall concrete, the concrete matrix region and the internal reinforcing phase region respectively. The internal reinforcing phase region includes the area where steel reinforcement is distributed inside the concrete structure.

[0010] The present invention also provides a system for testing and evaluating the radiation protection performance of concrete. The system is used to implement the aforementioned method and includes: a benchmark calibration module, an image acquisition module, a performance analysis module, and a quantitative evaluation module. The reference calibration module is used to irradiate a standard shield with a thickness gradient using X-rays, obtain a DR image of the standard shield, extract the average gray value under each gradient thickness, and construct an average gray value-equivalent thickness mapping model. The image acquisition module is used to irradiate the concrete specimen under test with X-rays in the same test environment as the benchmark calibration module, capture the penetrating rays through a flat panel detector and convert them into digital electrical signals to generate a DR image of the concrete specimen under test. The performance analysis module is used to extract the average gray value of the DR image of the concrete specimen to be tested, and calculate the equivalent thickness parameter of the concrete specimen to be tested based on the average gray value-equivalent thickness mapping model. The quantitative evaluation module is used to calculate the radiation shielding performance parameters of the concrete specimen under test based on the equivalent thickness parameter, so as to realize the quantitative evaluation of the overall and local radiation protection performance of the concrete structure.

[0011] Preferably, the benchmark calibration module includes: a measurement unit, a first function establishment unit, a second function establishment unit, and a model construction unit; The measurement unit is used to measure the X-ray radiation dose rate before transmission and the radiation dose rate after X-ray transmission through a standard shield using a Unidos dosimeter. The first function establishment unit is used to establish a linear function of average gray value and radiation dose rate after X-ray transmission through a standard shield based on the average gray value under each gradient thickness and the radiation dose rate after X-ray transmission through a standard shield. The second function establishment unit is used to establish a radiation dose rate-thickness exponential function after X-ray transmission through a standard shield and the thickness of the standard shield. The model building unit is used to construct an average gray-equivalent thickness mapping model based on the average gray-transmitted radiation dose rate linear function and the transmitted radiation dose rate-thickness exponential function.

[0012] Preferably, the process by which the second function establishment unit establishes a radiation dose rate-thickness exponential function after X-ray transmission through a standard shield and the thickness of the standard shield includes: ; in, This represents the radiation dose rate after X-ray transmission through a standard shielding device. This represents the X-ray radiation dose rate before transmission. The linear attenuation coefficient is... For thickness.

[0013] Preferably, the process of extracting the average grayscale value of the DR image of the concrete specimen under test from the performance analysis module, and calculating the equivalent thickness parameter of the concrete specimen under test based on the average grayscale-equivalent thickness mapping model, includes: By utilizing the spatial resolution characteristics of the DR image of the concrete specimen to be tested, grayscale is extracted from different regions in the DR image of the concrete specimen to be tested, so as to calculate the local equivalent thickness of the overall concrete, the concrete matrix region and the internal reinforcing phase region respectively. The internal reinforcing phase region includes the area where steel reinforcement is distributed inside the concrete structure.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) Using the average grayscale value of concrete DR test images as a medium, the radiation protection capability of different concretes can be uniformly represented by equivalent thickness, which has the advantages of being intuitive and convenient. 2) Compared to using a Unidos dosimeter to measure a single point on a test specimen, the grayscale value of a DR image can more effectively reflect the overall radiation protection performance of the structure.

[0015] This invention provides a comprehensive evaluation method for the radiation protection performance of structures that balances detection efficiency and spatial resolution. By introducing a spatial dimension analysis mechanism, this invention achieves effective decoupling and independent evaluation of the radiation protection performance of heterogeneous regions (such as the reinforcing steel phase and the concrete matrix) within concrete structures. It fills the technical gap that traditional single-point measurement methods cannot take into account local characteristics, and ultimately achieves a dual quantitative characterization of the structure's 'overall shielding effectiveness' and 'local feature distribution'.

[0016] Compared to the traditional Unidos dosimeter single-point detection method, this invention not only significantly improves detection timeliness and ease of operation, but also achieves a leap from 'point' to 'surface' in terms of data dimension, enabling more refined and high-precision radiation protection performance mapping analysis of complex concrete structures. Attached Figure Description

[0017] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. 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 diagram of the method for testing and evaluating the radiation protection performance of concrete according to an embodiment of the present invention; Figure 2This is a schematic diagram of the test apparatus used in this invention to perform radiation protection testing on concrete using DR technology. Figure 3 The following are two sets of linear functions of grayscale-transmission radiation dose rate under different environments and corresponding images obtained in an embodiment of the present invention. Figure 4 This is a schematic diagram of the radiation dose rate-steel thickness curve after transmission, according to an embodiment of the present invention. Figure 5 These are schematic diagrams of two sets of grayscale-equivalent steel thickness curves corresponding to embodiments of the present invention; Figure 6 The image is obtained using IPS software when performing DR testing on concrete according to an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1 like Figure 1 As shown, the present invention provides a method for testing and evaluating the radiation protection performance of concrete, comprising: S1. Use X-rays to irradiate a standard shield with a thickness gradient, obtain a DR image of the standard shield, extract the average gray value under each thickness gradient, and construct an average gray value-equivalent thickness mapping model. S2. Under the same test environment as S1, X-rays are used to irradiate the concrete specimen to be tested. The penetrating rays are captured by a flat panel detector and converted into digital electrical signals to generate DR images of the concrete specimen to be tested. S3. Extract the average gray value of the DR image of the concrete specimen to be tested, and calculate the equivalent thickness parameter of the concrete specimen to be tested based on the average gray value-equivalent thickness mapping model. S4. Based on the equivalent thickness parameter, calculate the radiation shielding performance parameters of the concrete specimen to be tested, so as to achieve a quantitative evaluation of the overall and local radiation protection performance of the concrete structure.

[0022] This invention proposes using digital radiography (DR) to conduct radiation protection tests on concrete test blocks. DR is a non-destructive testing technique that utilizes X-rays to irradiate objects. Its principle lies in the different absorption capacities of different media for X-rays. Therefore, X-rays penetrating the object can be received by a flat panel detector and converted into digital electrical signals, which are then processed by a computer to generate a high-resolution digital image. The advantages of DR testing include rapid imaging and accurate reflection of significant density differences within the object.

[0023] Since DR images can record tens of thousands of gray levels and have rich gray scales, this invention uses the average gray value of DR images as a characterization parameter to establish the radiation protection equivalence relationship between concrete specimens and standard steel plates.

[0024] The specific implementation process of this invention is as follows: S1 reference calibration: X-rays are used to irradiate a standard shield with a thickness gradient to obtain a DR image of the standard shield, and the average gray value under each thickness gradient is extracted to construct an average gray value-equivalent thickness mapping model.

[0025] In this embodiment, the standard shielding component is a standard steel plate.

[0026] First, standard steel plates of varying thicknesses were irradiated with X-rays (generated using an industrial CT scanner with an electron linear accelerator). The average grayscale values ​​of the corresponding DR images were then obtained using existing software. A scatter plot of the average grayscale values ​​of the DR images versus the thickness of the standard steel plates was plotted. Finally, a function was used to fit a curve representing the average grayscale value versus the equivalent steel thickness to determine the physical mapping relationship under specific experimental conditions.

[0027] This method, when evaluating the radiation shielding performance of concrete, does not equate the radiation shielding performance of the sheet steel plate (standard steel plate) with that of the internal mesh reinforcement of the concrete. Instead, it equates the standard steel plate with the entire concrete structure (standard steel plate is commonly used for this purpose in engineering, but other materials can also be used in this embodiment, as long as they are homogeneous). This is because both the standard steel plate and reinforced concrete function as a single, unified shielding surface when performing radiation shielding; therefore, the average grayscale value of the DR image is used as an indicator of radiation shielding performance.

[0028] The mesh reinforcement in concrete also contributes to radiation protection, so it can be analyzed locally to understand the radiation protection contribution of the reinforcement in the overall concrete based on the regional grayscale.

[0029] In practice, based on the average gray value under each gradient thickness and the radiation dose rate after X-ray transmission through the standard shield, a linear function of average gray value and radiation dose rate after transmission is established: the average gray value of the DR image is linearly related to the radiation dose rate after transmission captured by the detection plate, which is represented as a straight line passing through the origin on the function graph. This straight line needs to be drawn based on the results of DR tests of multiple sets of standard steel plates with different thicknesses on site.

[0030] Furthermore, the radiation dose rate transmitted through the standard steel plate has an exponential relationship with the thickness of the standard steel plate. Based on the radiation dose rate after X-ray transmission through the standard shield and the thickness of the standard shield, a radiation dose rate-thickness exponential function is established: ; in, This represents the radiation dose rate after X-ray transmission through a standard shielding device. This represents the X-ray radiation dose rate before transmission. The linear attenuation coefficient is... For thickness.

[0031] In determining the parameters, the X-ray radiation dose rate before transmission and the radiation dose rate after X-ray transmission through the standard shield can be measured using a Unidos dosimeter, the thickness can be measured using a vernier caliper, and the linear attenuation coefficient is determined by fitting curves to data from multiple sets of standard steel plates with different thicknesses using DR tests.

[0032] Therefore, the gray-equivalent steel thickness curve can be derived from the linear function of gray level and transmitted radiation dose rate and the exponential function of transmitted radiation dose rate and standard steel plate thickness. That is, based on the linear function of average gray level and transmitted radiation dose rate and the exponential function of transmitted radiation dose rate and thickness, the average gray level-equivalent thickness mapping model can be constructed.

[0033] in: y —Average grayscale value of DR image; t —Steel plate thickness.

[0034] S2 Image Acquisition: Under the same test environment as S1, the concrete specimen to be tested is irradiated with X-rays, and the penetrating rays are captured by a flat panel detector and converted into digital electrical signals to generate DR images of the concrete specimen to be tested.

[0035] Under the same test conditions as S1, using the following... Figure 2The apparatus shown uses an industrial CT linear accelerator (IPT2105) as the X-ray emitter to emit X-rays (the equipment used is model IPT2105, with a radiation energy of 4 MeV). The flat panel detector has a spatial resolution of 2.01 p / mm and a density resolution of 0.4%. During the experiment, the X-ray emitted from the emitter is absorbed and weakened by the concrete specimen under test and then detected by the flat panel detector. The data is transmitted to a computer for processing to generate a DR image.

[0036] Specifically, X-rays are used to irradiate the concrete specimen under test. The energy information carried by the penetrating rays is captured by a flat panel detector and converted into a digital signal to generate a DR image of the concrete specimen. The gray value of a pixel in the obtained DR image is positively correlated with the radiation dose rate received at that point: a higher gray value indicates less ray attenuation and weaker shielding ability of the medium; conversely, a lower gray value indicates that the ray is attenuated significantly and the shielding ability of the medium is strong.

[0037] The energy information carried by the penetrating rays is captured by a flat panel detector and converted into a digital signal. The process of generating a DR image of the concrete specimen to be tested includes: I. Energy Conversion: 1 (Photoelectric Conversion): X-rays first strike the scintillator layer of the flat panel detector, where the scintillator absorbs the X-ray photons and converts them into visible light; 2 (Photoelectric capture): Then, an amorphous silicon (a-Si) photodiode array closely attached to the scintillator receives this visible light and converts it into electrons (charge); 3 (charge storage): Thin-film transistors (TFTs) or complementary metal-oxide-semiconductor (CMOS) capacitors within each pixel unit temporarily store these charges.

[0038] II. Digitalization: 1 (Scan Drive): The control circuit turns on the TFT array row by row; 2 (Signal Integration): The analog charge stored in the capacitors of each pixel is transferred to the charge amplifier via the data line; 3 (Analog-to-Digital Conversion): The analog signal is amplified and sent to an A / D converter (Analog-to-Digital Converter). The A / D converter quantizes the continuous analog voltage value into discrete digital values ​​(grayscale values). 4 (Image Composition): The computer collects the digital codes of all pixels, arranges them according to their spatial positions, and finally generates an industrial digital image that can be seen on the screen, namely a DR image.

[0039] S3 performance analysis: Extract the average gray value of the DR image of the concrete specimen to be tested, and calculate the equivalent thickness parameter of the concrete specimen to be tested based on the average gray value-equivalent thickness mapping model.

[0040] In this embodiment, the equivalent thickness parameter is the equivalent steel thickness.

[0041] Utilizing the spatial resolution characteristics of DR images of concrete specimens, existing software is used to process and extract grayscale values ​​from different regions of the DR images of the concrete specimens to calculate the local equivalent thickness of the overall concrete, the concrete matrix region, and the internal reinforcing phase region, respectively.

[0042] The internal reinforcing phase region includes the area where the reinforcing steel is distributed within the concrete structure. By comparing the grayscale differences between the internal reinforcing phase region and the concrete matrix region, the contribution of the reinforcing steel to the overall radiation shielding performance of the structure is quantified. Specifically, the grayscale values ​​of the reinforced and unreinforced regions are extracted, and based on... Figure 5 The curve shown can be used to calculate the corresponding equivalent steel thickness. Then, through comparative analysis, it can be determined what percentage of the reinforcement effect is in the reinforced area.

[0043] S4 Quantitative Evaluation: Based on the equivalent thickness parameter, the radiation shielding performance parameters of the concrete specimen under test are calculated to achieve a quantitative evaluation of the overall and local radiation protection performance of the concrete structure. Based on the equivalent thickness parameter calculated by S3, parameters such as the half-value layer (HVL, the thickness of the medium required for the radiation dose rate to attenuate to half of its initial value), the tenth-value layer (TVL, the thickness of the medium required for the radiation dose rate to attenuate to one-tenth of its initial value), and the linear attenuation coefficient are calculated, thereby enabling the evaluation of the radiation shielding performance of concrete and its components. The stronger the radiation shielding performance of the shielding medium, the larger the linear attenuation coefficient, and the smaller the half-value layer and the tenth-value layer.

[0044] Specifically, the initial radiation dose rate is the X-ray radiation dose rate before transmission. When this value drops to half, the corresponding thickness of the shielding medium is half the thickness of that medium. When it drops to one-tenth, the corresponding thickness is one-tenth the thickness of that medium.

[0045] The linear attenuation coefficient of the standard steel plate is determined based on the fitted post-transmission radiation dose rate-thickness exponential function curve.

[0046] The half-value layer and one-tenth layer refer to the thickness of the medium that reduces the radiation dose rate to the corresponding value, and cannot be obtained solely from the radiation dose rate before transmission. For example... Figure 4 The radiation dose rate-steel thickness curve shows that the radiation dose rate at the left end of the curve when the steel thickness is 0 mm, which is the X-ray intensity before transmission, is 20.72 R / min. The steel thickness corresponding to half this value is the half-value layer of the steel. The half-value layer and one-tenth layer of concrete can be determined based on the radiation dose rate-thickness curve of the concrete after transmission (form similar to...). Figure 4 The curve shown is the same as that of the steel to determine this.

[0047] When fitting this curve for concrete, the thickness of different types of concrete can be directly measured, and the corresponding radiation dose rate can be obtained by substituting the grayscale of the concrete DR image into the previously fitted grayscale-radiation dose rate curve. Figure 3 ) was calculated.

[0048] In this embodiment, the "linear attenuation coefficient of the standard steel plate" is used to evaluate the radiation shielding performance of the steel plate. The purpose of determining this value is to plot... Figure 4 The images and curves shown are based on Figure 4 The steel thickness corresponding to a certain radiation dose rate can be obtained, and according to Figure 3 The radiation dose rate corresponding to a certain image gray level can be obtained, and the two can be combined to obtain the radiation dose rate. Figure 5 The curve represents the equivalent steel thickness at a certain gray level.

[0049] Figure 6 This is an image obtained using IPS software during a DR test of concrete. The area circled in red is the region where grayscale values ​​were extracted. After extraction, the information bar on the left will display information such as the maximum, minimum, and average grayscale values ​​of the region. Above the information is a statistical distribution map of the grayscale density in the region.

[0050] In summary, this invention provides a method for testing and evaluating the radiation protection performance of concrete. By introducing spatial dimension analysis capabilities, it can reasonably distinguish and evaluate the local radiation protection performance of different material regions within the concrete, thus achieving a dual quantitative analysis of the overall structural performance and local characteristics.

[0051] Example 2 Based on the same inventive concept, the present invention also provides a system for testing and evaluating the radiation protection performance of concrete, for implementing the method described in the foregoing embodiments. The system includes: a benchmark calibration module, an image acquisition module, a performance analysis module, and a quantitative evaluation module. The reference calibration module is used to irradiate a standard shield with a thickness gradient using X-rays, obtain a DR image of the standard shield, extract the average gray value under each gradient thickness, and construct an average gray value-equivalent thickness mapping model. The image acquisition module is used to irradiate the concrete specimen under test with X-rays in the same test environment as the benchmark calibration module, capture the penetrating rays through a flat panel detector and convert them into digital electrical signals to generate a DR image of the concrete specimen under test. The performance analysis module is used to extract the average gray value of the DR image of the concrete specimen to be tested, and calculate the equivalent thickness parameter of the concrete specimen to be tested based on the average gray value-equivalent thickness mapping model. The quantitative evaluation module is used to calculate the radiation shielding performance parameters of the concrete specimen under test based on the equivalent thickness parameter, so as to realize the quantitative evaluation of the overall and local radiation protection performance of the concrete structure.

[0052] Furthermore, in this embodiment, the benchmark calibration module includes: a measurement unit, a first function establishment unit, a second function establishment unit, and a model construction unit; The measurement unit is used to measure the X-ray radiation dose rate before transmission and the radiation dose rate after X-ray transmission through a standard shield using a Unidos dosimeter. The first function establishment unit is used to establish a linear function of average gray value and radiation dose rate after X-ray transmission through a standard shield based on the average gray value under each gradient thickness and the radiation dose rate after X-ray transmission through a standard shield. The second function establishment unit is used to establish a radiation dose rate-thickness exponential function after X-ray transmission through a standard shield and the thickness of the standard shield. The model building unit is used to construct an average gray-equivalent thickness mapping model based on the average gray-transmitted radiation dose rate linear function and the transmitted radiation dose rate-thickness exponential function.

[0053] Furthermore, in this embodiment, the process by which the second function establishment unit establishes a radiation dose rate-thickness exponential function after X-ray transmission through a standard shield and the thickness of the standard shield includes: ; in, This represents the radiation dose rate after X-ray transmission through a standard shielding device. This represents the X-ray radiation dose rate before transmission. The linear attenuation coefficient is... For thickness.

[0054] Furthermore, in this embodiment, the process of extracting the average grayscale value of the DR image of the concrete specimen under test from the performance analysis module, and calculating the equivalent thickness parameter of the concrete specimen under test based on the average grayscale-equivalent thickness mapping model, includes: By utilizing the spatial resolution characteristics of the DR image of the concrete specimen to be tested, grayscale is extracted from different regions in the DR image of the concrete specimen to be tested, so as to calculate the local equivalent thickness of the overall concrete, the concrete matrix region and the internal reinforcing phase region respectively. The internal reinforcing phase region includes the area where steel reinforcement is distributed inside the concrete structure.

[0055] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for testing and evaluating the radiation protection performance of concrete, characterized in that, The method includes: S1. Use X-rays to irradiate a standard shield with a thickness gradient, obtain a DR image of the standard shield, extract the average gray value under each thickness gradient, and construct an average gray value-equivalent thickness mapping model. S2. Under the same test environment as S1, X-rays are used to irradiate the concrete specimen to be tested. The penetrating rays are captured by a flat panel detector and converted into digital electrical signals to generate DR images of the concrete specimen to be tested. S3. Extract the average gray value of the DR image of the concrete specimen to be tested, and calculate the equivalent thickness parameter of the concrete specimen to be tested based on the average gray value-equivalent thickness mapping model. S4. Based on the equivalent thickness parameter, calculate the radiation shielding performance parameters of the concrete specimen to be tested, so as to achieve a quantitative evaluation of the overall and local radiation protection performance of the concrete structure.

2. The method according to claim 1, characterized in that, The method for extracting the average gray value under each gradient thickness in S1 and constructing the average gray value-equivalent thickness mapping model includes: The radiation dose rate before X-ray transmission and the radiation dose rate after X-ray transmission through a standard shield were measured using a Unidos dosimeter. Based on the average gray value under each gradient thickness and the radiation dose rate after X-ray transmission through a standard shield, a linear function of average gray value and radiation dose rate after transmission is established. Based on the radiation dose rate after X-ray transmission through a standard shield and the thickness of the standard shield, a radiation dose rate-thickness exponential function is established. Based on the linear function of average gray level-transmitted radiation dose rate and the exponential function of transmitted radiation dose rate-thickness, an average gray level-equivalent thickness mapping model is constructed.

3. The method according to claim 2, characterized in that, The method for establishing a radiation dose rate-thickness exponential function after X-ray transmission based on the radiation dose rate after X-ray transmission through a standard shield and the thickness of the standard shield includes: ； in, This represents the radiation dose rate after X-ray transmission through a standard shielding device. This represents the X-ray radiation dose rate before transmission. The linear attenuation coefficient is... For thickness.

4. The method according to claim 1, characterized in that, The method for extracting the average gray value of the DR image of the concrete specimen under test in step S3, and calculating the equivalent thickness parameter of the concrete specimen under test based on the average gray value-equivalent thickness mapping model, includes: By utilizing the spatial resolution characteristics of the DR image of the concrete specimen to be tested, grayscale is extracted from different regions in the DR image of the concrete specimen to be tested, so as to calculate the local equivalent thickness of the overall concrete, the concrete matrix region and the internal reinforcing phase region respectively. The internal reinforcing phase region includes the area where steel reinforcement is distributed inside the concrete structure.

5. A system for testing and evaluating the radiation shielding performance of concrete, said system being used to implement the method according to any one of claims 1-4, characterized in that, The system includes: a benchmark calibration module, an image acquisition module, a performance analysis module, and a quantitative evaluation module; The reference calibration module is used to irradiate a standard shield with a thickness gradient using X-rays, obtain a DR image of the standard shield, extract the average gray value under each gradient thickness, and construct an average gray value-equivalent thickness mapping model. The image acquisition module is used to irradiate the concrete specimen under test with X-rays in the same test environment as the benchmark calibration module, capture the penetrating rays through a flat panel detector and convert them into digital electrical signals to generate a DR image of the concrete specimen under test. The performance analysis module is used to extract the average gray value of the DR image of the concrete specimen to be tested, and calculate the equivalent thickness parameter of the concrete specimen to be tested based on the average gray value-equivalent thickness mapping model. The quantitative evaluation module is used to calculate the radiation shielding performance parameters of the concrete specimen under test based on the equivalent thickness parameter, so as to realize the quantitative evaluation of the overall and local radiation protection performance of the concrete structure.

6. The system according to claim 5, characterized in that, The benchmark calibration module includes: a measurement unit, a first function establishment unit, a second function establishment unit, and a model construction unit; The measurement unit is used to measure the X-ray radiation dose rate before transmission and the radiation dose rate after X-ray transmission through a standard shield using a Unidos dosimeter. The first function establishment unit is used to establish a linear function of average gray value and radiation dose rate after X-ray transmission through a standard shield based on the average gray value under each gradient thickness and the radiation dose rate after X-ray transmission through a standard shield. The second function establishment unit is used to establish a radiation dose rate-thickness exponential function after X-ray transmission through a standard shield and the thickness of the standard shield. The model building unit is used to construct an average gray-equivalent thickness mapping model based on the average gray-transmitted radiation dose rate linear function and the transmitted radiation dose rate-thickness exponential function.

7. The system according to claim 6, characterized in that, The second function establishment unit establishes a radiation dose rate-thickness exponential function based on the radiation dose rate after X-ray transmission through a standard shield and the thickness of the standard shield. The process includes: ； in, This represents the radiation dose rate after X-ray transmission through a standard shielding device. This represents the X-ray radiation dose rate before transmission. The linear attenuation coefficient is... For thickness.

8. The system according to claim 5, characterized in that, The process of extracting the average grayscale value of the DR image of the concrete specimen under test from the performance analysis module, and calculating the equivalent thickness parameter of the concrete specimen under test based on the average grayscale-equivalent thickness mapping model, includes: By utilizing the spatial resolution characteristics of the DR image of the concrete specimen to be tested, grayscale is extracted from different regions in the DR image of the concrete specimen to be tested, so as to calculate the local equivalent thickness of the overall concrete, the concrete matrix region and the internal reinforcing phase region respectively. The internal reinforcing phase region includes the area where steel reinforcement is distributed inside the concrete structure.

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