Method for identifying grade of radioactive metal material in nuclear power plant

Abstract

A method for identifying the grade of a highly radioactive metal material in a nuclear power plant. The method comprises the steps of: S1, using a laser-induced breakdown spectroscopy apparatus to perform spectrum collection on a radioactive metal material, so as to obtain average spectral information of the radioactive metal material; S2, performing similarity calculation on the obtained average spectral information of the radioactive metal material and the spectrum of a selected material of a known grade, so as to obtain a composite similarity; and S3, determining the grade of the radioactive metal material on the basis of the composite similarity. Rapid evaluation of the grade of a metal material independent of component analysis is realized, and the evaluation is quick in terms of speed and high in terms of accuracy.

Description

A method for identifying the grade of radioactive metal materials in nuclear power plants Technical Field

[0001] The present invention relates to the technical field of metal material spectrum analysis, and in particular to a method for identifying the brand of highly radioactive metal materials suitable for nuclear power plants. Background Art

[0002] Accurate identification and efficient detection of highly radioactive metal materials in nuclear power plants have always been a core concern. Due to the complex environment and radioactive materials in nuclear power plants, conventional detection methods such as spark direct reading or X-ray fluorescence spectrometry typically expose operators to radiation doses within a certain allowable range. Furthermore, they are not effective in identifying material grades. Therefore, an in-situ, remote, online measurement method is urgently needed that can both identify the grade of highly radioactive metal materials and protect the occupational health of operators.

[0003] In recent years, the development of Laser Induced Breakdown Spectroscopy (LIBS) has provided a new technical means for efficiently evaluating the service behavior of core component materials in nuclear power plants under harsh operating environments such as high radioactivity, high temperature, and high pressure. LIBS is a spectroscopic technique that uses the interaction of a high-power pulsed laser with the sample to generate a transient plasma. The high-temperature, high-density plasma radiates characteristic spectral lines of varying wavelengths. By analyzing the characteristic atomic or ion lines in the plasma emission spectrum, the technique enables qualitative or quantitative analysis of the sample.

[0004] Compared with traditional methods, LIBS technology offers powerful remote online detection capabilities that cannot be achieved by conventional detection methods. During the detection process, LIBS technology only "light contacts" the sample surface, and the mass of the sample ablated during the detection process is only in the microgram level, which has no impact on the entire system. It can obtain analysis results in real time with high accuracy and fast analysis speed. Among the new online monitoring technologies developed in nuclear power plants, it has obvious advantages.

[0005] Existing metal material grade identification technologies, such as the invention patent application number 201510372613.2, "Method and System for Identifying Metal Material Grades," primarily rely on a preset metal material content range and calculates the chi-square value by comparing the content range. This method requires judgment based on the content range of the measured material. Another example is the invention patent application number 201010576063.3, "A Method for Rapid and Non-destructive Identification of Metal Material Grades," which uses an X-ray fluorescence spectrometer. This method cannot measure the content of elements with lower atomic numbers and can only distinguish between carbon steel, medium- and low-alloy steel, and cannot determine the specific grade. None of these inventions are suitable for the rapid and efficient identification of highly radioactive metal materials in nuclear power plants.

[0006] Summary of the Invention

[0007] In view of this, the object of the present invention is to provide a method for identifying the grade of radioactive metal materials suitable for nuclear power plants.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for identifying the grade of radioactive metal materials in a nuclear power plant comprises the following steps:

[0010] S1: Using a laser-induced breakdown spectroscopy device to collect spectrum of the radioactive metal material to obtain average spectrum information of the radioactive metal material;

[0011] S2: Calculate the similarity between the average spectrum information of the obtained radioactive metal material and the spectrum of the selected known brand material to obtain a composite similarity;

[0012] S3: Determine the grade of the radioactive metal material based on the composite similarity.

[0013] According to some preferred implementation aspects of the present invention, the average spectrum information includes wavelength λ, intensity H and number of data points N.

[0014] According to some preferred implementation aspects of the present invention, the wavelength resolution is less than 0.07 nm, the wavelength range is 180 nm-1015 nm, and the number of data points N is greater than 7000.

[0015] According to some preferred implementation aspects of the present invention, the method for calculating the average spectrum information is: averaging the spectrum intensity of each wavelength, that is, n is the number of acquisitions.

[0016] According to some preferred implementation aspects of the present invention, the calculation of the similarity comprises the following steps:

[0017] 1): Calculate the similarity within the full wavelength range

[0018] 2): Calculate the similarity within the wavelength range of 225nm-325nm N1 is the number of data points in the wavelength range of 225nm-325nm;

[0019] 3): Calculate the similarity within the wavelength range of 335nm-450nm N2 is the number of data points in the wavelength range of 335nm-450nm;

[0020] 4): Calculate the similarity within the wavelength range of 450nm-600nm N3 is the number of data points in the wavelength range of 450nm-600nm;

[0021] 5): Calculate the composite similarity: S = X1r1+X2r2+X3r3+Xr.

[0022] According to some preferred implementation aspects of the present invention, in the calculation of the composite similarity, X1+X2+X3+X=1, wherein X is 0.2-0.25, X1 is 0.3-0.4, X2 is 0.25-0.3, and X3 is 0.15-0.2.

[0023] According to some preferred embodiments of the present invention, the method for determining the brand of the radioactive metal material based on the composite similarity is: if the composite similarity between the radioactive metal material and the selected known brand material is ≥0.910, then the radioactive metal material is the selected known brand material; if the composite similarity between the radioactive metal material and the selected known brand material is less than 0.910, then the selected known brand material is replaced and the above calculation is repeated.

[0024] According to some preferred embodiments of the present invention, the exposure dose rate of the radioactive metal material is greater than 0.5 mSv / h.

[0025] According to some preferred implementation aspects of the present invention, when collecting the spectrum, the distance between the laser induced breakdown spectroscopy device and the radioactive metal material is 3.5-7 m.

[0026] According to some preferred embodiments of the present invention, when collecting the spectrum, the number of collection times for each radioactive metal material is at least 10.

[0027] Due to the adoption of the above technical solution, compared with the existing technology, the benefits of the present invention are: the identification method of the brand of radioactive metal materials in nuclear power plants of the present invention realizes the rapid evaluation of metal material brands without relying on component analysis, with fast evaluation speed and high evaluation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] FIG1 is a comparison diagram of the average spectral information of the Z2CN19.10 material (1910-9) and the radioactive metal material (1-1-7) in the embodiment. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0031] The method for identifying the grade of radioactive metal materials in a nuclear power plant of this embodiment specifically includes the following steps:

[0032] S1: Spectral collection of metal materials of known grades

[0033] A remote laser-induced breakdown spectroscopy device is used to collect spectra of several metal materials of known grades within a distance of 3.5-7m to obtain average spectral information of several known grades of materials and form a database.

[0034] The average spectrum information includes wavelength λ, intensity H, and number of data points N. The wavelength resolution is less than 0.07 nm, the wavelength range is 180 nm-1015 nm, and the number of data points N is greater than 7000.

[0035] The number of collections for each known grade of material is at least 10.

[0036] S2: Spectral acquisition of target radioactive metal materials

[0037] A remote laser-induced breakdown spectroscopy device was used to collect spectra of radioactive metal materials at a distance of 3.5-7 meters to obtain their average spectral information. The exposure dose rate of the radioactive metal materials was greater than 0.5 mSv / h.

[0038] The average spectrum information includes wavelength λ, intensity H, and number of data points N. The wavelength resolution is less than 0.07 nm, the wavelength range is 180 nm-1015 nm, and the number of data points N is greater than 7000.

[0039] The number of acquisitions for each radioactive metal material is 10. The calculation method of the average spectrum information is: average the spectrum intensity of each wavelength, that is,

[0040] S3: Similarity calculation

[0041] The similarity between the spectrum information of the radioactive metal material and the spectrum of a certain known brand of material is calculated to obtain the composite similarity.

[0042] The similarity calculation method includes the following steps:

[0043] S3-1: Calculate similarity across the entire wavelength range

[0044] S3-2: Calculate the similarity of the wavelength range 225nm-325nm N1 is the number of data points in the wavelength range of 225nm-325nm;

[0045] S3-3: Calculate the similarity of the wavelength range 335nm-450nm N2 is the number of data points in the wavelength range of 335nm-450nm;

[0046] S3-4: Calculate the similarity in the wavelength range of 450nm-600nm N3 is the number of data points in the wavelength range of 450nm-600nm;

[0047] S3-5: Calculate composite similarity: S = X1r1+X2r2+X3r3+Xr

[0048] X1+X2+X3+X=1, wherein X is 0.2-0.25, X1 is 0.3-0.4, X2 is 0.25-0.3, and X3 is 0.15-0.2.

[0049] Under ideal conditions, two identical materials should be highly similar across the entire wavelength range, i.e., S = 1. However, in reality, due to variations in material surface conditions (such as corrosion) and the randomness of test signals during measurement, similarity across the entire wavelength range cannot be guaranteed. The 225nm-325nm wavelength range has the most characteristic spectral lines and the richest information, so similarity within this wavelength range is given a higher weight. The characteristic spectral lines between 225nm-450nm and 450nm-600nm are less important and are therefore given a lower weight.

[0050] S3: Determine the grade of radioactive metal materials based on composite similarity

[0051] If the composite similarity between the radioactive metal material and the set known brand material is ≥0.910, the radioactive metal material is the set known brand material; if the composite similarity between the radioactive metal material and the set known brand material is less than 0.910, the set known brand material is replaced and the above calculation is repeated until the composite similarity between the radioactive metal material and the selected known brand material is ≥0.910.

[0052] The following uses the identification of the material grade of a foreign object (1-1-7) in the core of a nuclear power plant as an example to specifically illustrate the method for identifying the grade of radioactive metal materials in a nuclear power plant of the present invention, which specifically includes the following steps:

[0053] S1: Spectral collection of Z2CN19.10 material

[0054] Using a remote laser-induced breakdown spectroscopy device, we collected spectra of several known metal materials at a distance of 3.5-7 meters, obtaining average spectral information for these materials and forming a database. This included collecting spectra of Z2CN19.10 material and obtaining its average spectral information (1910-9).

[0055] S2: Spectral acquisition of target highly radioactive metal materials

[0056] A remote laser-induced breakdown spectroscopy device was used to collect spectra of highly radioactive metal materials at a distance of 3.5-7 meters, obtaining their average spectral information (1-1-7). Figure 1 shows a comparison of the average spectral information of the Z2CN19.10 material (1910-9) and the radioactive metal material (1-1-7).

[0057] S3: Similarity calculation

[0058] The similarity between the spectral information of highly radioactive metal materials and the spectrum of Z2CN19.10 materials was calculated to obtain the composite similarity.

[0059] The similarity calculation method includes the following steps:

[0060] S3-1: Calculate similarity across the entire wavelength range N = 7485;

[0061] S3-2: Calculate the similarity of the wavelength range 225nm-325nm N1 is the number of data points in the wavelength range of 225nm-325nm = 1663;

[0062] S3-3: Calculate the similarity of the wavelength range 335nm-450nm N2 is the number of data points in the wavelength range of 335nm-450nm = 2224;

[0063] S3-4: Calculate the similarity in the wavelength range of 450nm-600nm N3 is the number of data points in the wavelength range of 450nm-600nm = 1201;

[0064] S3-5: Calculate composite similarity: S = X1r1 + X2r2 + X3r3 + Xr = 0.4 × 0.96276 + 0.25 × 0.93761 + 0.15 × 0.96611 + 0.2 × 0.90993 = 0.9464

[0065] X1+X2+X3+X=1, where X is 0.2, X1 is 0.4, X2 is 0.25, and X3 is 0.15.

[0066] S3: Determine the grade of highly radioactive metal materials based on composite similarity

[0067] The composite similarity between the highly radioactive metal material and the Z2CN19.10 material is ≥0.910, so the highly radioactive metal material is Z2CN19.10.

[0068] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A method for identifying the grade of radioactive metal materials in a nuclear power plant, characterized in that, It includes the following steps: S1: Use a laser-induced breakdown spectroscopy device to collect spectra of radioactive metal materials to obtain the average spectral information of the radioactive metal materials; S2: Calculate the similarity between the obtained average spectral information of the radioactive metal materials and the spectra of selected known-grade materials to obtain a composite similarity; S3: Determine the grade of the radioactive metal materials according to the composite similarity.

2. The recognition method according to claim 1, wherein The said average spectral information includes wavelength λ, intensity H, and the number of data points N.

3. The recognition method according to claim 2, characterized in that The wavelength resolution is less than 0.07 nm, the wavelength range is 180 nm - 1015 nm, and the number of data points N is greater than 7000.

4. The recognition method according to claim 2, wherein The calculation method of the average spectral information is as follows: average the spectral intensities at each wavelength, that is where n is the number of acquisitions.

5. The recognition method according to claim 2, wherein The calculation of the similarity includes the following steps: 1): Calculate the similarity within the full wavelength range 2): Calculate the similarity within the wavelength range of 225 nm - 325 nm N1 is the number of data points in the wavelength range of 225 nm - 325 nm; 3): Calculate the similarity within the wavelength range of 335nm - 450nm N2 is the number of data points in the wavelength range of 335 nm - 450 nm; 4): Calculate the similarity within the wavelength range of 450nm - 600nm N3 is the number of data points in the wavelength range of 450 nm - 600 nm; 5): Calculate the composite similarity: S = X1r1 + X2r2 + X3r3 + Xr.

6. The recognition method according to claim 5, wherein In the calculation of the said composite similarity, X1 + X2 + X3 + X = 1, where X ranges from 0.2 to 0.25, X1 ranges from 0.3 to 0.4, X2 ranges from 0.25 to 0.3, and X3 ranges from 0.15 to 0.

2.

7. The recognition method according to claim 1, wherein The method for determining the grade of the radioactive metal materials according to the composite similarity is as follows: If the composite similarity of the radioactive metal materials and the selected known-grade materials is ≥ 0.910, then the radioactive metal materials are the selected known-grade materials; if the composite similarity of the radioactive metal materials and the selected known-grade materials is less than 0.910, then replace the selected known-grade materials and repeat the above calculation.

8. The recognition method according to claim 1, wherein The contact dose rate of the said radioactive metal materials is greater than 0.5 mSv / h.

9. The recognition method according to claim 1, characterized in that When performing spectral collection, the distance between the laser-induced breakdown spectroscopy device and the radioactive metal materials is 3.5 - 7 m.

10. The recognition method according to claim 1, characterized in that When performing spectral collection, the number of collection times for each type of radioactive metal materials is at least 10 times.

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