Small sample neutron irradiation method for analyzing and detecting microstructure performance after irradiation

Abstract

The invention discloses a small sample neutron irradiation method for analyzing and detecting microstructure performance after irradiation. The small sample neutron irradiation method comprises the following steps: a, machining a groove in a blocky low-activation single crystal material by adopting a machining method; b, processing a material to be irradiated into a small sample matched with the size of the groove; c, loading a small sample to be irradiated into the groove of the blocky low-activation single crystal material; d, designing and processing an irradiation box according to an irradiation target, and loading the blocky low-activation single crystal material loaded with the to-be-irradiated sample into the irradiation box; e, transferring the irradiation box into a reactor to carry out neutron irradiation; f, after the irradiation is completed, disassembling the irradiation box in the hot chamber, taking out the blocky low-activation single crystal material loaded with the irradiated sample, and temporarily storing and cooling the blocky low-activation single crystal material; and g, transferring the cooled block-shaped low-activation single crystal material loaded with the irradiated sample out of the hot chamber, and carrying out subsequent analysis and detection after irradiation. The method has the advantages of being high in efficiency, good in economical efficiency, small in harm, good in environmental friendliness and the like. The method has high economic value and good application prospect in the fields of material irradiation engineering assessment, irradiation effect fundamental research and the like.

Description

Technical Field

[0001] The invention belongs to the field of nuclear technology application, and in particular relates to a small sample neutron irradiation method for analyzing and detecting microstructure performance after irradiation. Background Art

[0002] The Chinese government attaches great importance to building a clean, low-carbon, safe and efficient energy system and improving the energy supply security capability. Among them, nuclear energy is a very important form of energy, and various new reactors (III+ generation, IV generation fission reactors, hybrid reactors, fusion reactors, etc.) are developing unprecedentedly. Before the materials are put into service in these reactors, they need to be neutron irradiated in the research reactor, and post-irradiation analysis and testing are carried out to clarify the neutron irradiation damage mechanism, and pass the neutron irradiation engineering assessment to ensure that their performance under service conditions meets the use requirements, ensure reliability, and ensure nuclear safety.

[0003] The samples to be irradiated in the reactor need to be designed and processed into different shapes and sizes according to the different research purposes, such as "dog bone" shaped samples for measuring tensile mechanical properties (typical length is about 100mm), sheet samples for measuring thermal conductivity (typical size is: Φ6×2mm), rod samples for measuring thermal expansion coefficient (typical size is: Φ6×25mm), etc.

[0004] For microstructure performance analysis and testing (such as optical microscopy, microhardness, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, focused ion beam processing and transmission electron microscopy, etc.), the sample often only needs to be very small (less than 1mm). Domestic and foreign researchers often use the following two methods to prepare for irradiation experiments of such small samples: 1. Prepare special small samples for irradiation in the pile, with a typical shape and size of Φ3mm disc-shaped samples; 2. After the aforementioned large samples are irradiated and tested accordingly, the required small samples are cut out in the hot chamber. For the first method, the sample size is relatively large, and each type of material needs to prepare a separate sample. In general, the activity of the irradiated sample is relatively large, which poses a greater hazard to the experimenters and the post-irradiation analysis and testing equipment, and generates a large amount of radioactive waste; for the second method, cutting in the hot chamber is more restricted, and a manipulator is required to complete the sample loading, clamping, equipment startup, unloading and other operations, which is relatively time-consuming and labor-intensive, and will generate more radioactive dust and waste liquid. In addition, for different types of material samples, when these two methods are used for microstructural performance analysis and testing, common experimental steps such as sample loading, vacuuming, and sample unloading need to be carried out separately, which is inefficient and uneconomical.

[0005] In summary, it is necessary to propose an improved small sample neutron irradiation method for microstructural performance analysis and detection in order to improve detection efficiency, reduce radiation dose, and reduce radioactive waste. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a small sample neutron irradiation method for post-irradiation microstructural performance analysis and detection, so as to solve the problems of low efficiency, high radiation dose, and large amount of radioactive waste generated in the process of post-irradiation microstructural performance analysis and detection in the prior art.

[0007] The present invention provides a small sample neutron irradiation method for analyzing and detecting microstructure performance after irradiation, characterized in that it comprises the following steps:

[0008] a. Processing grooves on bulk low-activated single crystal materials;

[0009] b. Processing the material to be irradiated into a small sample matching the cross-sectional dimensions of the groove;

[0010] c. Transfer the small sample into the groove;

[0011] d. Loading the bulk low-activated single crystal material loaded with a small sample into the irradiation box;

[0012] e. Transport the irradiation box to the irradiation channel in the reactor for neutron irradiation;

[0013] f. After the irradiation is completed, the irradiation box is disassembled in the hot chamber, and the block of low-activated single crystal material is taken out and temporarily stored for cooling;

[0014] g. The cooled low-activated single crystal material is transported out of the heat chamber for subsequent analysis and testing after irradiation.

[0015] Further, in step a, the cross section of the groove is an inverted T-shape.

[0016] Further, in step a, the groove opening is arranged on the opening side of the block low-activation single crystal material, the upper part of the inverted T-shaped cross-section of the groove is located on the surface of the block low-activation single crystal material, the lower part of the inverted T-shaped cross-section extends inward along the surface of the block low-activation single crystal material, and the groove extends along the opening side of the block low-activation single crystal material to the side opposite to the opening, and does not penetrate the opposite side of the opening.

[0017] Furthermore, in step a, the bulk low-activation single crystal material is Si, graphite, diamond or SiC.

[0018] Furthermore, in step b, the shape of the small sample is T-shaped or I-shaped.

[0019] Further, in step c, small samples are sequentially loaded into the grooves of the bulk low-activation single crystal material.

[0020] Furthermore, in step c, an inert material is used to isolate small samples that are prone to diffusion reactions, and after the small samples are loaded, the ends of the grooves are sealed with an inert material.

[0021] Furthermore, in step c, the inert material is a material that does not react with the small sample, such as SiC, Al2O3, ZrO2, etc.

[0022] Furthermore, in step c, laser marking or diamond knife marking is used to mark and distinguish the corresponding positions of different small samples on the bulk low-activated single crystal material.

[0023] Furthermore, in step d, the material, shape, size, water flow form, and filling gas of the irradiation box are determined according to the irradiation temperature, irradiation injection, and post-irradiation analysis and detection items.

[0024] Further, in step d, the irradiation box is configured to be shared with other irradiated samples.

[0025] Further, in step e, the irradiation position and irradiation time of the irradiation box depend on the irradiation target.

[0026] Further, in step f, the irradiation box that is not welded and sealed is disassembled by a robot.

[0027] Further, in step f, a cutting machine in the hot chamber is used to disassemble the welded and sealed irradiation box.

[0028] Furthermore, in step f, the temporary cooling time depends on the type and activity of radionuclides produced after the small sample is irradiated.

[0029] Furthermore, in step g, the post-irradiation analysis and testing includes optical microscopy, microhardness, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, focused ion beam processing and transmission electron microscopy.

[0030] Furthermore, in step g, during the analysis and detection after irradiation, the bulk low-activated single crystal material and the small sample can be detected as a whole.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] 1. Multiple groups of samples of different types can be irradiated at a time to obtain a large amount of experimental data, with high efficiency and good economy;

[0033] 2. The activity of the sample after irradiation is small, which poses less harm to the experimenters and the analytical and testing equipment after irradiation, and has good safety;

[0034] 3. It produces less radioactive waste and is environmentally friendly. It has high economic value and good application prospects in the fields of material irradiation engineering assessment and basic research on irradiation effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of a block-shaped low-activation single crystal material with grooves processed in Example 1 of the present invention;

[0036] Figure 2 It is a schematic diagram of a small sample of the material to be irradiated that matches the groove size in Example 1 of the present invention;

[0037] Figure 3 This is a schematic diagram of loading a small sample to be irradiated into a groove of a block-shaped low-activation single crystal material in Example 1 of the present invention;

[0038] Figure 4 This is a schematic diagram of the irradiation box in Example 1 of the present invention. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereby. Those skilled in the art can make further improvements to these technical solutions based on the contents disclosed in this specification without violating the spirit and scope of the present invention.

[0040] Example 1

[0041] The present invention provides a small sample neutron irradiation method for analyzing and detecting microstructure performance after irradiation, characterized in that:

[0042] The following steps are involved:

[0043] a. Processing grooves on bulk low-activated single crystal materials;

[0044] like Figure 1 As shown, an inverted T-shaped groove is machined on a single crystal Si with a length, width and height of 20mm×20mm×2mm by a mechanical processing method. The length, width and height of the bottom of the groove are 15mm×1mm×0.5mm, and the length, width and height of the top of the groove are 15mm×0.5mm×0.5mm. The processing parameters all use positive tolerances, and the size of the positive tolerance is 0.03mm~0.05mm.

[0045] b. Processing the material to be irradiated into a small sample matching the cross-sectional dimensions of the groove;

[0046] like Figure 2 As shown, five samples of NbTiVZr alloy, Zr-4 alloy, 6061 aluminum alloy, pure aluminum, and FeCrAl alloy to be irradiated are processed into small samples with thickness and width matching the dimensions of the above-mentioned inverted T-shaped groove, with a bottom length, width, and height of 1mm×1mm×0.5mm and a top length, width, and height of 1mm×0.5mm×0.5mm. Negative tolerance is used in the processing parameters, and the size of the negative tolerance is -0.03mm to -0.05mm.

[0047] c. Transfer the small sample into the groove;

[0048] like Figure 3As shown, the five small samples to be irradiated are loaded into the grooves of the bulk single crystal Si material in sequence. The samples are separated by inert material Al2O3. The size of Al2O3 is different only in the width direction, with a width of 0.5 mm. The processing parameters use a negative tolerance, with a negative tolerance of -0.03 mm to -0.05 mm. In order to distinguish different samples, after the small samples are loaded, the corresponding positions on the single crystal Si are marked with sample numbers 1 to 5 by laser. Four parallel samples are set for each sample, and the sample numbers a to d are marked by laser.

[0049] d. Loading the bulk low-activated single crystal material loaded with a small sample into the irradiation box;

[0050] like Figure 4 As shown, this irradiation experiment has no special requirements for the irradiation temperature. A water-passing irradiation method is used to process a groove with a length, width and height of 20mm×20mm×2mm on a sample box made of nuclear-grade 6061 aluminum alloy. The processing parameters use positive tolerances with a size of 0.03mm to 0.05mm. The block single crystal Si material loaded with the small sample to be irradiated is placed in the groove, and the irradiation box is packaged in a snap-fit ​​manner.

[0051] e. Transport the irradiation box to the irradiation channel in the reactor for neutron irradiation;

[0052] Use a manipulator and a transfer device to transfer the irradiation box to a specific irradiation channel in the reactor for neutron irradiation. Avoid bumping during operation. The cumulative fast neutron (>0.1MeV) dose is ~0.2×10 20 n / cm 2 .

[0053] f. After the irradiation is completed, the irradiation box is disassembled in the hot chamber, and the block of low-activated single crystal material is taken out and temporarily stored for cooling;

[0054] The irradiation box that has completed irradiation is transferred to the hot chamber using a manipulator and a transfer device. The box cover is unscrewed using a manipulator, and the bulk single crystal Si material containing the irradiated small sample is transferred to a sample box covered with a cushion. After cooling for one month, the surface radiation dose is measured to be less than 100μSv / h.

[0055] g. The cooled low-activated single crystal material is transported out of the heat chamber for subsequent analysis and testing after irradiation.

[0056] The cooled bulk single crystal Si material loaded with small irradiated samples is transported out of the heat chamber by a robot for subsequent post-irradiation optical microscopy, microhardness, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, focused ion beam processing and transmission electron microscopy analysis and testing.

[0057] Further, in step a, the cross section of the groove is an inverted T-shape.

[0058] Further, in step a, the groove opening is arranged on the opening side of the block low-activation single crystal material, the upper part of the inverted T-shaped cross-section of the groove is located on the surface of the block low-activation single crystal material, the lower part of the inverted T-shaped cross-section extends inward along the surface of the block low-activation single crystal material, and the groove extends along the opening side of the block low-activation single crystal material to the side opposite to the opening, and does not penetrate the opposite side of the opening.

[0059] Furthermore, in step a, the bulk low-activation single crystal material is Si, graphite, diamond or SiC.

[0060] Furthermore, in step b, the shape of the small sample is T-shaped or I-shaped, and the processing parameters use negative tolerances. The size of the negative tolerance depends on the degree of swelling of the material after neutron irradiation and is determined by physical calculations.

[0061] Further, in step c, small samples are sequentially loaded into the grooves of the bulk low-activation single crystal material.

[0062] Furthermore, in step c, inert materials are used to isolate small samples that are prone to diffusion reactions. After the small samples are loaded, the ends of the grooves are sealed with inert materials to prevent the samples from moving.

[0063] Furthermore, in step c, the inert material is a material that does not react with the small sample, such as SiC, Al2O3, ZrO2, etc.

[0064] Furthermore, in step c, laser marking or diamond knife marking is used to mark and distinguish the corresponding positions of different small samples on the bulk low-activated single crystal material.

[0065] Furthermore, in step d, the material, shape, size, water flow form, and filling gas of the irradiation box are determined according to the irradiation temperature, irradiation injection, and post-irradiation analysis and detection items.

[0066] Furthermore, in step d, the irradiation box is configured to be shared with other irradiated samples to reduce irradiation costs and the amount of radioactive waste.

[0067] Furthermore, in step e, the irradiation box is transported to a specific irradiation position in the reactor by a manipulator and a transport device to carry out neutron irradiation. Bumps are avoided during the operation. The irradiation position and irradiation time of the irradiation box depend on the irradiation target.

[0068] Further, in step f, the irradiation box that is not welded and sealed is disassembled by a robot.

[0069] Further, in step f, a cutting machine in the hot chamber is used to disassemble the welded and sealed irradiation box.

[0070] Furthermore, in step f, the temporary cooling time depends on the type and activity of radionuclides produced after the small sample is irradiated.

[0071] Furthermore, in step g, the post-irradiation analysis and testing includes optical microscopy, microhardness, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, focused ion beam processing and transmission electron microscopy.

[0072] Furthermore, in step g, during the analysis and detection after irradiation, the bulk low-activated single crystal material and the small sample can be detected as a whole, without the need to unload the small samples separately and then detect them separately, so as to save the time consumed in common experimental steps such as sample loading, vacuuming, and sample unloading, thereby improving efficiency and reducing experimental costs.

[0073] The experimental results show that the small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection of the present invention overcomes the problems of low efficiency, large radiation dose, and large amount of radioactive waste generated by the existing methods. In this embodiment, a total of 20 neutron irradiated samples of five different types were obtained in a single pile-in experiment, and a large amount of valuable microstructure performance analysis and detection experimental data after neutron irradiation were obtained efficiently at a low cost. The optimized design of the sample shape and size greatly reduces the sample mass, so that the radiation dose of the sample and the base after irradiation is greatly reduced, and the harm to the experimental personnel and instruments and equipment is reduced. Compared with the existing method, the amount of radioactive waste generated by the method of the present invention is greatly reduced, which reduces the difficulty and cost of subsequent radioactive waste disposal.

[0074] The present invention is described in detail above in combination with specific implementation methods and exemplary examples. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments; the above description cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, the technical solution of the present invention and its implementation methods may be subjected to a variety of equivalent substitutions, modifications or improvements, all of which fall within the scope of the present invention; the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A small sample neutron irradiation method for analyzing and detecting microstructure performance after irradiation, characterized in that: The following steps are involved: a. Processing grooves on bulk low-activated single crystal materials; b. processing the material to be irradiated into a small sample matching the cross-sectional dimensions of the groove; c. transferring the small sample into the groove; d. loading the bulk low-activated single crystal material loaded with the small sample into the irradiation box; e. transporting the irradiation box to the irradiation channel in the reactor for neutron irradiation; f. After the irradiation is completed, the irradiation box is disassembled in the hot chamber, the block of low-activated single crystal material is taken out, and it is temporarily stored for cooling; g. The cooled block low-activated single crystal material is transported out of the heat chamber for subsequent analysis and testing after irradiation.

2. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that: In step a, the cross section of the groove is an inverted T-shape.

3. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 2, characterized in that: In step a, the groove opening is arranged on the opening side of the block low-activation single crystal material, the upper part of the inverted T-shaped cross-section of the groove is located on the surface of the block low-activation single crystal material, and the lower part of the inverted T-shaped cross-section extends inward along the surface of the block low-activation single crystal material, and the groove extends along the opening side of the block low-activation single crystal material to the side opposite to the opening, and does not penetrate the opposite side of the opening.

4. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that: In step a, the bulk low-activation single crystal material is Si, graphite, diamond or SiC.

5. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that: In step b, the shape of the small sample is T-shaped or I-shaped.

6. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that: In step c, the small samples are sequentially loaded into the grooves of the bulk low-activation single crystal material.

7. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 6, characterized in that: In step c, the small sample that is prone to diffusion reaction is isolated by using an inert material, and after the small sample is loaded, the end of the groove is sealed by using an inert material.

8. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 7, characterized in that: In step c, the inert material is a material that does not react with the small sample, such as SiC, Al2O3, ZrO2, etc.

9. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 8, characterized in that: In step c, laser marking or diamond knife marking is used to mark and distinguish the corresponding positions of different small samples on the bulk low-activation single crystal material.

10. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that: In step d, the material, shape, size, water flow form, and filling gas of the irradiation box are determined according to the irradiation temperature, irradiation injection, and post-irradiation analysis and detection items.

11. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that: In step d, the irradiation box is configured to be shared with other irradiation samples.

12. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that: In step e, the irradiation position and irradiation time of the irradiation box depend on the irradiation target.

13. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that: In step f, the irradiation box that is not welded and sealed is disassembled by a robot.

14. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that: The welded sealed irradiation box was disassembled using a cutting machine in the hot chamber.

15. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that: In step f, the temporary cooling time depends on the type and activity of radionuclides produced after the small sample is irradiated.

16. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that: In step g, the post-irradiation analysis and testing includes optical microscopy, microhardness, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, focused ion beam processing and transmission electron microscopy.

17. The small sample neutron irradiation method for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that: In step g, during the analysis and detection after irradiation, the bulk low-activated single crystal material and the small sample can be detected as a whole.

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