Method for preparing sensitivity test block based on ray attenuation coefficient blending

Abstract

The invention provides a method for preparing a sensitivity test block based on ray attenuation coefficient allocation, relates to the technical field of nuclear fuel element production ray imaging, and aims to realize high-precision ray irradiation characteristic fitting of the sensitivity test block and a to-be-tested workpiece material under a low-cost condition. Comprising the following steps: acquiring equivalent energy E and linear attenuation coefficient spatial distribution of a penetrating X-ray of a workpiece material to be detected; acquiring first equivalent alloy component information of a sensitive block preparation material; performing component adjustment on the first equivalent alloy component information based on linear attenuation coefficient spatial distribution of a to-be-detected workpiece material tool to obtain second equivalent alloy component information; and preparing the sensitivity test block based on the sensitive block preparation material and the second equivalent alloy component information. The method has the advantages that the special expensive material sensitivity test block is effectively replaced on the premise of keeping the main body of the radiographic detection technology unchanged, so that the nondestructive detection cost of the special expensive material is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear fuel element production radiation imaging, and in particular to a method for preparing a sensitivity test block based on radiation attenuation coefficient. Background Art

[0002] In the field of non-destructive testing of radiographic imaging, it is usually necessary to use sensitivity test blocks of the same material as the sample to be tested to determine the effectiveness and accuracy of radiographic testing. Generally speaking, a series of sensitivity test blocks containing defects are artificially manufactured using the materials and processes of the production process of the sample to be tested. During radiographic testing, the defect status of the original workpiece to be tested is determined by observing the size of the defects on the test blocks. The non-destructive testing process is completed after qualification is determined through technical input and testing procedures.

[0003] Traditionally, sensitivity test blocks are generally manufactured using the same material and process. When the material of the workpiece to be tested is special and the number of tests is small, such as uranium-zirconium alloys and rare precious metals in the nuclear material field, the testing unit may not have the ability to process sensitivity test blocks of the same material. Even if it is capable of manufacturing sensitivity test blocks of the same material, the special nature of the material will cause a significant increase in testing costs. However, if other materials with similar density are used for indirect judgment, there is a problem of heavy reliance on experience and inaccurate sensitivity.

[0004] Therefore, there is an urgent need to formulate a sensitivity test block to achieve low-cost and high-precision fitting of radiation exposure characteristics, thereby solving the problem of processing sensitivity test blocks for radiation detection of special and expensive materials. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing a sensitivity test block based on the preparation of a radiation attenuation coefficient, which can achieve high-precision radiation irradiation characteristic fitting of the sensitivity test block and the material of a workpiece to be tested under low-cost conditions.

[0006] The embodiments of the present invention are implemented by the following technical solutions:

[0007] A method for preparing a sensitivity test block based on a radiation attenuation coefficient comprises the following steps:

[0008] Obtain the equivalent energy E and linear attenuation coefficient spatial distribution of the penetrating X-ray of the material of the workpiece to be inspected;

[0009] Acquire first equivalent alloy composition information of the material for preparing the sensitive block based on the average atomic coefficient and average density of the material of the workpiece to be detected;

[0010] Based on the spatial distribution of the linear attenuation coefficient of the material of the workpiece to be detected, the first equivalent alloy composition information is adjusted to obtain the second equivalent alloy composition information;

[0011] A sensitivity test block is prepared based on the sensitive block preparation material and the second equivalent alloy composition information.

[0012] Preferably, the method for obtaining the equivalent energy E of the penetrating X-ray of the material of the workpiece to be detected and the spatial distribution of the linear attenuation coefficient is:

[0013] Obtaining the equivalent energy E based on the average atomic number and size of the material of the workpiece to be detected;

[0014] The spatial distribution of the linear attenuation coefficient is obtained by Monte Carlo particle transport software.

[0015] Preferably, the method for obtaining the first equivalent alloy composition information of the material for preparing the sensitive block based on the average atomic coefficient and average density of the material of the workpiece to be detected is:

[0016] Establishing a functional relationship between the first equivalent alloy composition information and the average atomic coefficient and a functional relationship between the first equivalent alloy composition information and the average density based on the molar ratio variable;

[0017] The average atomic coefficient and average density of the material of the sensitive block are preset to be respectively the same as the average atomic coefficient and average density of the material of the workpiece to be detected;

[0018] The first equivalent alloy composition information is obtained based on the functional relationship.

[0019] Preferably, the method for obtaining the average density of the material of the workpiece to be inspected is: obtaining the average density by the Achilles drainage method or obtaining the average density by chemical composition and phase diagram calculation.

[0020] Preferably, the method for obtaining the average density by calculating the chemical composition and phase diagram is: The method for obtaining the average density of the material of the workpiece to be detected is to calculate by calculating the chemical composition and phase diagram:

[0021] Obtaining the atomic weight and molar ratio of each element in the material of the workpiece to be detected;

[0022] Get the density ρ:

[0023] ρ=∑ i a i *m i ;

[0024] Among them, a i and m i are the atomic weight and molar ratio of the ith element respectively.

[0025] Preferably, the method for adjusting the first equivalent alloy composition information based on the spatial distribution of the linear attenuation coefficient of the material tool of the workpiece to be detected to obtain the second equivalent alloy composition information is:

[0026] Simulating the simulated spatial attenuation of X-ray irradiation having the equivalent energy E based on the first equivalent alloy composition information by Monte Carlo particle transport software;

[0027] The first equivalent alloy composition information is adjusted until the difference between the simulated spatial attenuation and the target spatial attenuation of the material of the workpiece to be detected irradiated by X-rays with the equivalent energy E does not exceed a preset threshold, thereby obtaining the second equivalent alloy composition information.

[0028] Preferably, the method for adjusting the first equivalent alloy composition information is:

[0029] Adjusting the first equivalent alloy composition information, obtaining a difference between the simulated spatial attenuation and the target spatial attenuation of the material of the workpiece to be detected irradiated by X-rays having the equivalent energy E, and obtaining a ratio of the difference to the target spatial attenuation;

[0030] Repeat the above steps until the ratio does not exceed the preset error threshold, and obtain the second equivalent alloy composition information.

[0031] Preferably, the preset error threshold is 1%.

[0032] Preferably, the method for preparing the sensitivity test block based on the sensitive block preparation material and the second equivalent alloy composition information is:

[0033] Forming by mixing, ball milling and sintering;

[0034] A sensitivity test block having the same size in the penetration direction as the workpiece to be detected is prepared by machining a through hole.

[0035] Preferably, the sensitive block is made of tungsten-iron alloy.

[0036] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0037] The present invention solves the processing problem of the sensitivity test block for ray detection of special and expensive materials, and can prepare a sensitivity test block with lower cost and higher cost performance, thereby effectively replacing the sensitivity test block of special and expensive materials and significantly reducing the cost of non-destructive detection of special and expensive materials.

[0038] The present invention realizes high-precision characteristic simulation by approximating various characteristics of the sensitivity test block, including shape and spatial distribution of linear attenuation coefficient, to the corresponding characteristics of the element to be detected, and can also realize accurate non-destructive testing cost at low cost.

[0039] The present invention effectively solves the difficult problem in the process of X-ray detection of high-density and high-atomic-number materials, and has a strong prospect of use in non-destructive detection of nuclear fuel and nuclear materials, and also has a strong prospect of use in other industries involving internal quality detection of high-density and high-atomic-number workpieces. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic flow chart of a method for preparing a sensitivity test block based on the radiation attenuation coefficient provided in Example 1 of the present invention;

[0041] Figure 2 Schematic diagram of the illumination of the workpiece to be tested and the sensitivity test block provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0043] Example 1

[0044] This embodiment provides a method for preparing a sensitivity test block based on the radiation attenuation coefficient. Figure 1 , including the following steps:

[0045] Step S1: Obtaining the equivalent energy E and the spatial distribution of the linear attenuation coefficient of the penetrating X-ray of the material of the workpiece to be detected;

[0046] Step S2: obtaining first equivalent alloy composition information of the material for preparing the sensitive block based on the average atomic coefficient and average density of the material of the workpiece to be detected;

[0047] Step S3: adjusting the first equivalent alloy composition information based on the spatial distribution of the linear attenuation coefficient of the material of the workpiece to be detected to obtain the second equivalent alloy composition information;

[0048] Step S4: preparing a sensitivity test block based on the sensitive block preparation material and the second equivalent alloy composition information.

[0049] As a preferred solution, the sensitive block preparation material in this embodiment can be tungsten-iron alloy.

[0050] The design principles of this implementation are as follows:

[0051] The radiographic imaging of the workpiece to be inspected, including but not limited to traditional film imaging, digital DR imaging, and three-dimensional CT imaging, is essentially the distribution of the radiation attenuation coefficient of the atoms of the workpiece material in three-dimensional space, which is imaged on the film or detector through mathematical transformation. In theory, by preparing entities with the same distribution of radiation attenuation coefficient μ, it is possible to achieve exactly the same detection image under the action of radiation. There are five types of interactions between radiation and matter: Compton effect, photoelectric effect, electron pair effect, Rayleigh scattering, and light-nuclear interaction. Under the conditions of a monoenergetic narrow beam, the relationship between radiation intensity and the distance of the transmitted material is as follows:

[0052] N=N0e -μd ;

[0053] Among them, N0 and N are the number of photons before and after passing through the material (equivalent to the intensity of X-rays), d is the thickness of the material, μ is the linear attenuation coefficient of the material, and the light intensity received by the detector or film is directly related to N. Therefore, refer to Figure 2 When the radiation source conditions are consistent, the imaging quality at the detector end is only related to the linear attenuation coefficient and the penetration distance of the workpiece being inspected.

[0054] In other words, the equivalence of imaging quality can be guaranteed by ensuring that the linear attenuation coefficient and the transmission distance of the sensitivity test block are the same as those of the material to be tested. Therefore, when the spatial distribution of the linear attenuation coefficient and the transmission distance of the workpiece to be tested and the sensitivity test block are the same, that is, μ(x, y, z) = μ'(x, y, z), the same ray attenuation can be generated, and the same ray intensity can be obtained on the detector side, and then the same detection image can be obtained. Under this condition, it is not required that the composition of the workpiece to be tested and the composition and processing technology of the sensitivity test block are the same. When the composition of the sample to be tested is determined, the sensitivity test block of rare and precious materials can be effectively replaced by heterogeneous conventional materials through the calculation and allocation of different ray attenuation coefficients of heterogeneous materials. Therefore, the main purpose of this embodiment is to find a low-cost alternative alloy as a sensitive block preparation material, and based on the second equivalent alloy composition information, the sensitive block preparation material and the material of the workpiece to be detected have the same linear attenuation coefficient, and then it can be processed into a shape corresponding to the workpiece to be detected and used as a sensitivity test block.

[0055] Based on the solution of this embodiment, it is possible to use low-cost alloys to replace expensive workpiece materials to be tested as sensitivity test blocks, and at the same time, by determining appropriate alloy components to achieve the same radiation irradiation characteristics as the workpiece material to be tested, ensure consistent detection effects.

[0056] Example 2

[0057] This embodiment is based on the technical solution of Embodiment 1 and further explains the specific implementation methods of each step.

[0058] In this embodiment, the method for obtaining the equivalent energy E and the spatial distribution of the linear attenuation coefficient of the penetrating X-ray of the material of the workpiece to be detected in step S1 is:

[0059] Obtaining the equivalent energy E based on the average atomic number and size of the material of the workpiece to be detected;

[0060] The spatial distribution of the linear attenuation coefficient is obtained by Monte Carlo particle transport software.

[0061] The principle of obtaining the spatial distribution of the linear attenuation coefficient by Monte Carlo particle transport software is that in the simulation of X-ray penetration of metal materials, Monte Carlo simulation can effectively handle complex physical processes and material properties. Based on the relationship expression of N0 and N mentioned in Example 1, for example, Monte Carlo particle transport software (Monte Carlo N-Particle, referred to as MCNP) is used to generate random numbers to simulate the interaction between X-rays and metal materials, and the generated random numbers are used to construct an instance or scenario of the problem. For example, the X-ray source, the geometric shape and physical properties of the metal material are set in the MCNP software, and the required calculations or analyses are performed on the constructed model to obtain results. For example, the absorption of X-rays by metal materials of different thicknesses can be calculated. Repeat the above steps multiple times, using different random numbers each time, and the statistical characteristics of the problem, such as expected value, variance, confidence interval, etc., can be obtained through multiple simulations. By analyzing the results of multiple simulations, the statistical characteristics of the problem can be obtained.

[0062] On the other hand, in step S2, the method for obtaining the first equivalent alloy composition information of the material for preparing the sensitive block based on the average atomic coefficient and average density of the material of the workpiece to be detected is:

[0063] Establishing a functional relationship between the first equivalent alloy composition information and the average atomic coefficient and a functional relationship between the first equivalent alloy composition information and the average density based on the molar ratio variable;

[0064] The average atomic coefficient and average density of the material of the sensitive block are preset to be respectively the same as the average atomic coefficient and average density of the material of the workpiece to be detected;

[0065] The first equivalent alloy composition information is obtained based on the functional relationship.

[0066] This step mainly uses the first equivalent alloy composition to find a composition that is similar to the average density and average atomic coefficient of the workpiece material to be tested. For example, in this embodiment, tungsten-iron alloy is used to simulate uranium-zirconium alloy, and the first equivalent alloy composition information W can be obtained first.x Fe y Based on W x Fe y The calculated average density and average atomic coefficient are similar to the average density and average atomic coefficient of the workpiece material to be tested. When calculating, x and y can be used as unknown variables to be solved to establish the average density and average atomic coefficient of the sensitivity test block material, and then establish equations with the known average density and average atomic coefficient of the workpiece material to be tested to solve the first equivalent alloy composition information W. x Fe y It is particularly noted that the linear attenuation coefficient of the sensitive block preparation material under equivalent energy E can be obtained by querying the dosimetry table.

[0067] As a preferred solution, the method for obtaining the average density of the material of the workpiece to be inspected is: obtaining the average density by the Achilles drainage method or obtaining the average density by calculating the chemical composition and phase diagram.

[0068] Furthermore, the method for obtaining the average density by calculating the chemical composition and phase diagram is as follows: The method for obtaining the average density of the material of the workpiece to be detected is to calculate by calculating the chemical composition and phase diagram:

[0069] Obtaining the atomic weight and molar ratio of each element in the material of the workpiece to be detected;

[0070] Get the density ρ:

[0071] ρ=∑ i a i *m i ;

[0072] Among them, a i and m i are the atomic weight and molar ratio of the ith element respectively.

[0073] In obtaining the first equivalent alloy composition information W x Fe y Later, W x Fe y The average atomic number and average density of are the same as those of the uranium-zirconium alloy to be tested, which can ensure that the attenuation behavior is basically similar under the equivalent energy E of the X-ray. However, since the X-ray equivalent energy E and the average atomic number are too rough, a more accurate linear attenuation coefficient spatial distribution requires fine-tuning of the tungsten-iron composition information. Therefore, it is also necessary to find the second equivalent alloy composition information W by adjusting the first equivalent alloy composition information. x′ Fe y′ , making the spatial distribution of the linear attenuation coefficients of the two materials closer.

[0074] In addition, in step S3, the method for adjusting the first equivalent alloy composition information based on the spatial distribution of the linear attenuation coefficient of the material tool of the workpiece to be detected to obtain the second equivalent alloy composition information is:

[0075] Simulating the simulated spatial attenuation of X-ray irradiation having the equivalent energy E based on the first equivalent alloy composition information by Monte Carlo particle transport software;

[0076] The first equivalent alloy composition information is adjusted until the difference between the simulated spatial attenuation and the target spatial attenuation of the material of the workpiece to be detected irradiated by X-rays with the equivalent energy E does not exceed a preset threshold, thereby obtaining the second equivalent alloy composition information.

[0077] On this basis, the method for adjusting the first equivalent alloy composition information is preferably:

[0078] Adjusting the first equivalent alloy composition information, obtaining a difference between the simulated spatial attenuation and the target spatial attenuation of the material of the workpiece to be detected irradiated by X-rays having the equivalent energy E, and obtaining a ratio of the difference to the target spatial attenuation;

[0079] Repeat the above steps until the ratio does not exceed the preset error threshold, and obtain the second equivalent alloy composition information.

[0080] As a further preferred solution, the preset error threshold is 1%.

[0081] After fine-tuning, the densities of the uranium-zirconium alloy and the tungsten-iron alloy may be different, but the equivalent conversion of the linear attenuation coefficient and the attenuation distance is guaranteed. Finally, the fine-tuned tungsten-iron alloy can effectively replace the original uranium-zirconium alloy linear attenuation coefficient.

[0082] Finally, the method for preparing the sensitivity test block based on the sensitive block preparation material and the second equivalent alloy composition information in step S4 is:

[0083] Forming by mixing, ball milling and sintering;

[0084] A sensitivity test block having the same size in the penetration direction as the workpiece to be detected is prepared by machining a through hole.

[0085] Based on the determined second equivalent alloy composition information, the sensitive block preparation material is obtained, and the sensitive block preparation material is processed to obtain a sensitivity test block that is consistent with the shape, size and irradiation characteristics of the workpiece to be tested.

[0086] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a sensitivity test block based on the radiation attenuation coefficient, characterized in that: The following steps are involved: Obtain the equivalent energy E and linear attenuation coefficient spatial distribution of the penetrating X-ray of the material of the workpiece to be inspected; Acquire first equivalent alloy composition information of the material for preparing the sensitive block based on the average atomic coefficient and average density of the material of the workpiece to be detected; Based on the spatial distribution of the linear attenuation coefficient of the material of the workpiece to be detected, the first equivalent alloy composition information is adjusted to obtain the second equivalent alloy composition information; A sensitivity test block is prepared based on the sensitive block preparation material and the second equivalent alloy composition information.

2. The method for preparing a sensitivity test block based on the radiation attenuation coefficient according to claim 1, characterized in that: The method for obtaining the equivalent energy E of the penetrating X-ray of the material of the workpiece to be detected and the spatial distribution of the linear attenuation coefficient is: Obtaining the equivalent energy E based on the average atomic number and size of the material of the workpiece to be detected; The spatial distribution of the linear attenuation coefficient is obtained by Monte Carlo particle transport software.

3. The method for preparing a sensitivity test block based on the radiation attenuation coefficient according to claim 2 is characterized in that: The method for obtaining the first equivalent alloy composition information of the material for preparing the sensitive block based on the average atomic coefficient and average density of the material of the workpiece to be detected is: Establishing a functional relationship between the first equivalent alloy composition information and the average atomic coefficient and a functional relationship between the first equivalent alloy composition information and the average density based on the molar ratio variable; The average atomic coefficient and average density of the material of the sensitive block are preset to be respectively the same as the average atomic coefficient and average density of the material of the workpiece to be detected; The first equivalent alloy composition information is obtained based on the functional relationship.

4. The method for preparing a sensitivity test block based on the radiation attenuation coefficient according to claim 3 is characterized in that: The method for obtaining the average density of the material of the workpiece to be detected is: obtaining the average density by the Achilles drainage method or obtaining the average density by chemical composition and phase diagram calculation.

5. The method for preparing a sensitivity test block based on the radiation attenuation coefficient according to claim 4 is characterized in that: The method for obtaining the average density by calculating the chemical composition and phase diagram is as follows: The method for obtaining the average density of the material of the workpiece to be detected is to calculate by calculating the chemical composition and phase diagram: Obtaining the atomic weight and molar ratio of each element in the material of the workpiece to be detected; Get the density ρ: p=∑ i a i *m i ; Among them, a i and m i are the atomic weight and molar ratio of the ith element respectively.

6. The method for preparing a sensitivity test block based on the radiation attenuation coefficient according to claim 1, characterized in that: The method for adjusting the first equivalent alloy composition information based on the spatial distribution of the linear attenuation coefficient of the material of the workpiece to be detected to obtain the second equivalent alloy composition information is: Simulating the simulated spatial attenuation of X-ray irradiation having the equivalent energy E based on the first equivalent alloy composition information by Monte Carlo particle transport software; The first equivalent alloy composition information is adjusted until the difference between the simulated spatial attenuation and the target spatial attenuation of the material of the workpiece to be detected irradiated by X-rays with the equivalent energy E does not exceed a preset threshold, thereby obtaining the second equivalent alloy composition information.

7. The method for preparing a sensitivity test block based on the radiation attenuation coefficient according to claim 6, characterized in that: The method for adjusting the first equivalent alloy composition information is: Adjusting the first equivalent alloy composition information, obtaining a difference between the simulated spatial attenuation and the target spatial attenuation of the material of the workpiece to be detected irradiated by X-rays having the equivalent energy E, and obtaining a ratio of the difference to the target spatial attenuation; Repeat the above steps until the ratio does not exceed the preset error threshold, and obtain the second equivalent alloy composition information.

8. The method for preparing a sensitivity test block based on the radiation attenuation coefficient according to claim 7 is characterized in that: The preset error threshold is 1%.

9. The method for preparing a sensitivity test block based on the radiation attenuation coefficient according to claim 1, characterized in that: The method for preparing a sensitivity test block based on the sensitive block preparation material and the second equivalent alloy composition information is: Forming by mixing, ball milling and sintering; A sensitivity test block having the same size in the penetration direction as the workpiece to be detected is prepared by machining a through hole.

10. The method for preparing a sensitivity test block based on the radiation attenuation coefficient according to claim 1, characterized in that: The sensitive block is made of tungsten-iron alloy.

Images