A small sample neutron irradiation method for post-irradiation microstructure performance analysis detection

Abstract

The application discloses a small sample neutron irradiation method for analyzing and detecting microstructure performance after irradiation, and comprises the following steps: a. a groove is machined on a blocky low-activation single crystal material by a mechanical machining method; b. a material to be irradiated is machined into a small sample matched with the size of the groove; c. the small sample to be irradiated is loaded into the groove of the blocky low-activation single crystal material; d. according to an irradiation target, an irradiation box is designed and machined, and the blocky low-activation single crystal material loaded with the sample to be irradiated is loaded into the irradiation box; e. the irradiation box is transported into a reactor to carry out neutron irradiation; f. after the irradiation is completed, the irradiation box is disassembled in a hot cell, the blocky low-activation single crystal material loaded with the sample after irradiation is taken out and temporarily stored for cooling; g. the blocky low-activation single crystal material loaded with the sample after irradiation and cooled is transported out of the hot cell to carry out subsequent analysis and detection after irradiation. The application has the characteristics of high efficiency, good economy, small harm and good environmental protection. The application has high economic value and good application prospect in the fields of material irradiation engineering examination and irradiation effect basic research.

Description

Technical Field

[0001] This invention belongs to the field of nuclear technology applications, and in particular relates to a neutron irradiation method for analyzing and detecting the microstructure properties of small samples after irradiation. Background Technology

[0002] Nuclear energy is a very important form of energy, and various new types of reactors (Generation III+, Generation IV fission reactors, hybrid reactors, fusion reactors, etc.) are being developed at an unprecedented pace. Before materials are put into service in these reactors, they need to be irradiated with neutrons in the research reactor, and post-irradiation analysis and testing should be carried out to elucidate the neutron irradiation damage mechanism. They also need to pass neutron irradiation engineering tests to ensure that their performance under service conditions meets the requirements, guaranteeing reliability and ensuring nuclear safety.

[0003] Depending on the research objective, the samples to be irradiated in the reactor need to be designed and processed into different shapes and sizes, such as "dog bone" shaped samples (typical length about 100 mm) for tensile mechanical property measurement, sheet-like samples (typical size: Φ6×2 mm) for thermal conductivity measurement, and rod-like samples (typical size: Φ6×25 mm) for thermal expansion coefficient measurement, etc.

[0004] For microstructural 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), samples often require only a very small size (less than 1 mm). Researchers both domestically and internationally typically prepare such small samples for irradiation experiments using two methods: 1. Preparing dedicated small samples for in-feed irradiation, typically circular discs with a shape and size of Φ3 mm; 2. After the aforementioned large samples have undergone irradiation and corresponding testing, cutting out the required small samples within a heated chamber. For the first method, the sample size is relatively large, and separate samples are required for each type of material. Overall, the irradiated samples have high activity, posing a significant risk to researchers and post-irradiation analytical equipment, and generating a large amount of radioactive waste. For the second method, cutting within the heated chamber is more restrictive, requiring the use of robotic arms for sample loading, clamping, equipment startup, and unloading, which is relatively time-consuming and labor-intensive, and generates a large amount of radioactive dust and waste liquid. Furthermore, for different types of material samples, both methods require separate experimental steps for microstructure performance analysis, such as sample loading, vacuuming, and sample unloading, which is inefficient and uneconomical.

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

[0006] In view of this, the purpose of the present invention is to provide a neutron irradiation method for small sample microstructure performance analysis and detection after irradiation, thereby solving the problems of low efficiency, large radiation dose, and large amount of radioactive waste generated in the prior art during the microstructure performance analysis and detection process after irradiation.

[0007] This invention provides a neutron irradiation method for small samples used in the analysis and detection of microstructure properties after irradiation, characterized by comprising the following steps:

[0008] a. Grooves are machined into bulk low-activation single crystal materials;

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

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

[0011] d. Load the bulk low-activation single crystal material containing the small sample into the irradiation box;

[0012] e. Transfer the irradiation box to the irradiation channel inside the reactor to carry out neutron irradiation;

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

[0014] g. The cooled, bulk low-activation single crystal material is transferred out of the hot chamber for subsequent post-irradiation analysis and testing.

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

[0016] Furthermore, in step a, the groove opening is located on the opening side of the bulk low-activation single crystal material. The upper part of the inverted T-shaped groove cross-section is located on the surface of the bulk low-activation single crystal material, and the lower part of the inverted T-shaped groove extends inward along the surface of the bulk low-activation single crystal material. The groove extends along the opening side of the bulk low-activation single crystal material to the side opposite to the opening, but does not penetrate the side opposite to 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 small sample is T-shaped or I-shaped.

[0019] Furthermore, 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 the small sample phase that is prone to diffusion reaction. After the small sample is loaded, the end of the groove is 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-activation single crystal material.

[0023] Furthermore, in step d, the material, shape, size, water passage method, and filling gas of the irradiation box are determined according to the different irradiation temperature, irradiation flux, and post-irradiation analysis and testing items.

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

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

[0026] Furthermore, in step f, the unsealed irradiation box is disassembled using a robotic arm.

[0027] Furthermore, in step f, the welded and sealed irradiation box is disassembled using a cutting machine inside the hot chamber.

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

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

[0030] Furthermore, in step g, during post-irradiation analysis and detection, the bulk low-activation 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 different types of samples can be irradiated in a single irradiation, obtaining a large amount of experimental data, which is highly efficient and economical;

[0033] 2. The irradiated samples have low activity, posing minimal harm to laboratory personnel and post-irradiation analytical instruments and equipment, and are therefore highly safe.

[0034] 3. It generates little radioactive waste and is environmentally friendly. It has high economic value and good application prospects in fields such as materials irradiation engineering assessment and basic research on irradiation effects. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the blocky low-activation single crystal material with grooves processed in Embodiment 1 of the present invention;

[0036] Figure 2 This is a schematic diagram of a small sample of the material to be irradiated, which matches the size of the groove in Embodiment 1 of the present invention;

[0037] Figure 3 This is a schematic diagram of a small sample to be irradiated being loaded into a groove in a blocky low-activation single crystal material in Embodiment 1 of the present invention;

[0038] Figure 4 This is a schematic diagram of the irradiation box in Embodiment 1 of the present invention. Detailed Implementation

[0039] The present invention will be further described below with reference to specific embodiments, but this does not limit the scope of protection of the present invention. Those skilled in the art can make further improvements to these technical solutions based on the content disclosed in this specification without departing from the spirit and scope of the present invention.

[0040] Example 1

[0041] This invention provides a neutron irradiation method for small samples used in the analysis and detection of microstructure properties after irradiation, characterized by comprising the following steps:

[0042] a. Grooves are machined into bulk low-activation single crystal materials;

[0043] like Figure 1 As shown, an inverted T-shaped groove was machined on a single-crystal Si with dimensions of 20mm×20mm×2mm using a machining method. The bottom of the groove has dimensions of 15mm×1mm×0.5mm, and the top of the groove has dimensions of 15mm×0.5mm×0.5mm. All machining parameters used positive tolerances, with a positive tolerance range of 0.03mm to 0.05mm.

[0044] b. Process the material to be irradiated into a small sample that matches the cross-sectional dimensions of the groove;

[0045] like Figure 2 As shown, five samples to be irradiated—NbTiVZr alloy, Zr-4 alloy, 6061 aluminum alloy, pure aluminum, and FeCrAl alloy—were processed into small samples with thicknesses and widths matching the dimensions of the inverted T-shaped grooves mentioned above. The bottom dimensions were 1mm × 1mm × 0.5mm, and the top dimensions were 1mm × 0.5mm × 0.5mm. Negative tolerances were used for the processing parameters, with a negative tolerance range of -0.03mm to -0.05mm.

[0046] c. Transfer the small sample into the groove;

[0047] like Figure 3As shown, the aforementioned five small samples to be irradiated were sequentially loaded into the grooves of the bulk single-crystal Si material. The samples were isolated from each other using an inert material, Al2O3. The dimensions of the Al2O3 material differed only in the width direction, with a width of 0.5 mm. Negative tolerances were used in the processing parameters, with a tolerance range of -0.03 mm to -0.05 mm. To distinguish between different samples, after loading the small samples, the sample numbers 1 to 5 were marked on the corresponding positions on the single-crystal Si using a laser. Four parallel samples were prepared for each type of sample, and the sample numbers a to d were marked on them using a laser.

[0048] d. Load the bulk low-activation single crystal material containing the small sample into the irradiation box;

[0049] like Figure 4 As shown, this irradiation experiment has no special requirements for irradiation temperature and adopts a water-permeable irradiation method. A groove with a length, width, and height of 20mm × 20mm × 2mm was machined on a sample box made of nuclear-grade 6061 aluminum alloy. The machining parameters used positive tolerance, with a positive tolerance of 0.03mm to 0.05mm. A block of single-crystal Si material containing the small sample to be irradiated was placed in the groove, and the irradiation box was sealed using a snap-fit ​​method.

[0050] e. Transfer the irradiation box to the irradiation channel inside the reactor to carry out neutron irradiation;

[0051] The irradiation box is transported to a specific irradiation channel inside the reactor using a robotic arm and a transfer device to carry out neutron irradiation. During the operation, collisions are avoided, and the cumulative fast neutron (>0.1MeV) fluence is ~0.2×1020n / cm2.

[0052] f. After irradiation is completed, the irradiation box is disassembled in the hot chamber, and the blocky low-activation single crystal material is taken out and temporarily stored for cooling.

[0053] The irradiated box, after irradiation, was transferred to the hot chamber using a robotic arm and a transfer device. The box lid was then unscrewed by the robotic arm, and the blocky single-crystal Si material containing the irradiated small sample was transferred to a sample box lined with soft padding. After cooling for one month, the surface radiation dose was measured to be <100 μSv / h.

[0054] g. The cooled, bulk low-activation single crystal material is transferred out of the hot chamber for subsequent post-irradiation analysis and testing.

[0055] A robotic arm is used to transfer the cooled, bulk single-crystal Si material loaded with irradiated small samples out of the hot chamber for subsequent analysis and testing, including optical microscopy, microhardness analysis, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, focused ion beam processing, and transmission electron microscopy.

[0056] Furthermore, in step a, the cross-section of the groove is an inverted T-shape.

[0057] Furthermore, in step a, the groove opening is located on the opening side of the bulk low-activation single crystal material. The upper part of the inverted T-shaped groove cross-section is located on the surface of the bulk low-activation single crystal material, and the lower part of the inverted T-shaped groove extends inward along the surface of the bulk low-activation single crystal material. The groove extends along the opening side of the bulk low-activation single crystal material to the side opposite to the opening, but does not penetrate the side opposite to the opening.

[0058] Furthermore, in step a, the bulk low-activation single crystal material is Si, graphite, diamond, or SiC.

[0059] Furthermore, in step b, 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, which is determined by physical calculations.

[0060] Furthermore, in step c, small samples are sequentially loaded into the grooves of the bulk low-activation single crystal material.

[0061] Furthermore, in step c, an inert material is used to isolate the small sample phase that is prone to diffusion reaction. After the small sample is loaded, the end of the groove is sealed with an inert material to prevent the sample from moving.

[0062] Furthermore, in step c, the inert material is a material that does not react with the small sample, such as SiC, Al2O3, ZrO2, etc.

[0063] 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-activation single crystal material.

[0064] Furthermore, in step d, the material, shape, size, water passage method, and filling gas of the irradiation box are determined according to the different irradiation temperature, irradiation flux, and post-irradiation analysis and testing items.

[0065] Furthermore, in step d, the irradiation box is set to be shared with other irradiated samples to reduce irradiation costs and the amount of radioactive waste.

[0066] Furthermore, in step e, the irradiation box is transported to a specific irradiation location within the reactor using a robotic arm and a transfer device to carry out neutron irradiation. During the operation, collisions are avoided, and the irradiation location and irradiation time of the irradiation box depend on the irradiation target.

[0067] Furthermore, in step f, the unsealed irradiation box is disassembled using a robotic arm.

[0068] Furthermore, in step f, the welded and sealed irradiation box is disassembled using a cutting machine inside the hot chamber.

[0069] Furthermore, in step f, the temporary storage cooling time depends on the type and activity of the radionuclides produced after the small sample is irradiated.

[0070] Furthermore, in step g, the post-irradiation analysis and detection include optical microscopy, microhardness analysis, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, focused ion beam processing, and transmission electron microscopy.

[0071] Furthermore, in step g, during post-irradiation analysis and detection, the bulk low-activation single crystal material and the small sample can be detected as a whole, without having to unload the small sample separately for individual detection. This saves time spent on common experimental steps such as sample loading, vacuuming, and sample unloading, thereby improving efficiency and reducing experimental costs.

[0072] Experimental results show that the neutron irradiation method for small-sample microstructure performance analysis and detection of the present invention overcomes the problems of low efficiency, high radiation dose, and large amount of radioactive waste generated by existing methods. In this embodiment, a single reactor-entry experiment yielded 20 neutron-irradiated samples of five different types, obtaining a large amount of valuable experimental data on microstructure performance analysis and detection after neutron irradiation at a low cost and high efficiency. The optimized design of sample shape and size greatly reduces sample mass, resulting in a significant reduction in the radiation dose to the sample and base after irradiation, thus reducing the harm to experimental personnel and equipment. Compared with existing methods, the method of the present invention generates a significantly reduced amount of radioactive waste, lowering the difficulty and cost of subsequent radioactive waste disposal.

[0073] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments; the above descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present invention without departing from the spirit and scope of the present invention, and all such modifications and improvements fall within the scope of the present invention; the scope of protection of the present invention is determined by the appended claims.

Claims

1. A neutron irradiation method for analyzing and detecting the microstructure properties of small samples after irradiation, characterized in that, Includes the following steps: a. Grooves are machined into bulk low-activation single crystal materials; b. Process the material to be irradiated into a small sample that matches the cross-sectional dimensions of the groove; c. Transfer the small sample into the groove; d. Load the bulk low-activation single crystal material, which has already been loaded with the small sample, into the irradiation box; e. Transfer the irradiation box to the irradiation channel inside the reactor to carry out neutron irradiation; f. After irradiation is completed, the irradiation box is disassembled in the hot chamber, the bulk low-activation single crystal material is taken out and temporarily stored for cooling; g. The cooled bulk low-activation single crystal material is transferred out of the hot chamber for subsequent post-irradiation analysis and testing.

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

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

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

8. The neutron irradiation method for small samples used 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.

9. The neutron irradiation method for small samples used for post-irradiation microstructure performance analysis and detection according to claim 8, characterized in that, The inert material is SiC, Al2O3, or ZrO2.

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

11. The neutron irradiation method for small samples used for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that, In step d, the material, shape, size, water passage method, and filling gas of the irradiation box are determined according to the different irradiation temperature, irradiation dose, and post-irradiation analysis and detection items.

12. The neutron irradiation method for small samples used 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 irradiated samples.

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

14. The neutron irradiation method for small samples used for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that, In step f, the unsealed irradiation box is disassembled by a robotic arm.

15. The neutron irradiation method for small samples used for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that, The welded seal of the irradiation box is removed using a cutting machine inside the heated chamber.

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

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

18. The neutron irradiation method for small samples used for post-irradiation microstructure performance analysis and detection according to claim 1, characterized in that, In step g, during post-irradiation analysis and detection, the bulk low-activation single crystal material and the small sample as a whole are detected.

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