This standard specifies the metallographic inspection method for nuclear fuel rod welds. This standard is applicable to the metallographic inspection of the penetration depth and defects of the girth welds and plugging welds of zirconium alloy (Zr-2, Zr-4) cladding tube fuel rods, and is also applicable to the metallographic inspection of the molten zone, heat-affected zone and matrix of the weld. The metallographic defect inspection and penetration depth inspection of the girth welds of zirconium alloy guide tubes in fuel assemblies can also refer to the provisions of this standard. GB/T 11809-1998 Metallographic Inspection of Nuclear Fuel Rods in Pressurized Water Reactors GB/T11809-1998 Standard Download Decompression Password: www.bzxz.net

ICS27.120.30
National Standard of the People's Republic of Chinabzxz.net
GB/T11809—1998
Metallographic examination for weldseam of nuclear fuel rod used in PWR
Metallographic examination for weldseam of nuclear fuel rod used in PWR Issued on March 20, 1998
State Administration of Technical Supervision
Implementation on September 1, 1998
GB/T11809-1998
This standard specifies the metallographic examination method for weldseam of nuclear fuel rod used in PWR to replace GB11809-89 Metallographic Examination of Nuclear Fuel Rod Welds. This standard partially modifies the sample preparation method in Article 5.2 of GB11809-89 and adds the method for determining the effective penetration value to ensure the accuracy of penetration measurement.
This standard replaces GB11809-89 from the date of entry into force. This standard is proposed by China National Nuclear Corporation. This standard is under the jurisdiction of the Standardization Institute of China National Nuclear Corporation. The drafting unit of this standard is the State-owned August 12 Plant. The main drafter of this standard is Zhang Ke.
1 Scope
National Standard of the People's Republic of China
Metallographic examination for weldseam of nuclear fuel rod used in PWR
Metallographic examination for weldseam of nuclear fuel rod used in PWR This standard specifies the metallographic examination method for nuclear fuel rod welds. GB/T11809—1998
Replaces GB11809--89
This standard is applicable to the metallographic examination of the penetration depth and defects of the girth weld and plugging weld of zirconium alloy (Zr-2, Zr-4) cladding tube fuel rods, and is also applicable to the metallographic examination of the fusion zone, heat-affected zone and matrix of the weld. The metallographic defect inspection and penetration depth inspection of the girth weld of zirconium alloy guide tubes in fuel assemblies can also refer to the provisions of this standard. 2 Symbols and definitions
This standard uses the following symbols and definitions:
Girth weld penetration S Ring penetration of the welding welding Cladding tube and end plug welding fusion thickness, unit: mm (see Figure 1). Hole plugging weld penetration S Tank penetration of these al welding The minimum fusion thickness measured along the central axis of the plugging weld, unit: mm (see Figure 2). Wall thickness G thickness of the tube
Cladding tube wall thickness, unit: mm (see Figure 1). Melted zone depth P Cup depth of the melted zone The maximum depth of the melted zone between the cladding tube and the end plug welding, unit: mm (see Figure 1). Hole plugging weld thickness P thickness of these al welding The minimum fusion thickness of the plugging weld, unit: mm (see Figure 2). G
S=min(Si,S,)
Figure 1 Definition of measurement parameters of girth weld
Effective penetration Sleast thickness of sound part of weld zoneFigure 2 Definition of measurement parameters of plugging weld
Minimum fusion thickness of welding at the fusion point of cladding tube and end plug after eliminating the influence of defects in girth weld, unit: mm. Undercut
Approved by the State Administration of Technical Supervision on March 20, 1998 and implemented on September 1, 1998
GB/T11809—1998
The phenomenon of undercutting of cladding tube wall due to welding gas or other reasons. 3 Principle of method
3.1 Thin film etching method
Thin film etching method is also called thin film dyeing method. After the sample is etched by the selected thin film etchant, as a result of the chemical reaction between the etchant and the various tissues on the grinding surface, a layer of uneven chemical reaction deposits is formed on the grinding surface, covering the various tissues. Under the irradiation of white light, light interference occurs. The lighter-colored deposits covering the molten zone of the weld form a clear boundary with the darker-colored matrix, which can be clearly distinguished and measured with the naked eye or a reading microscope. 3.2 Chemical Etching Method
Chemical etching method is to select appropriate chemical etching liquid to etch the polished inspection surface. The etching process is a chemical dissolution process. The etchant first dissolves the amorphous layer on the surface of the grinding surface, and then chemically dissolves the grain boundaries. As the etching continues, the etchant will dissolve the grains. Since the orientation of each grain on the grinding surface is different, the dissolution rate is different. After etching, each grain will expose the most densely packed atomic plane and form a different angle with the grinding surface. Under the vertical light of the microscope, the grain structure of different brightness will be displayed. 3.3 Hot dyeing method
The hot dyeing method is used to inspect the melting zone, heat-affected zone and matrix structure (referred to as the three-zone structure) of the fuel rod weld. The hot dyeing method is to place the polished sample in 500C air and heat it to form a layer of oxide film on the ground surface. At the same temperature, due to the difference in grain orientation, the oxidation ability varies, resulting in different thicknesses of oxide films formed on different grains. White light is used to interfere between oxide films to display grain structures of different colors.
4 Reagents
4.1 Oxalic acid (H, C, 02H, 0): chemically pure
4.2 Nitric acid (HNO): 65%~68%, chemically pure. 4.3 Hydrofluoric acid (HF): 40%, chemically pure. 4.4 Ethylene glycol (HOCH, CHOH): analytically pure. 4.5 Deionized water: resistivity ≥1×10°0.m. 4.6 Polishing liquid: 45 mL of nitric acid (4.2) plus 10 mL of hydrofluoric acid (4.3) plus 45 mL of water (4.5). 4.7 Polishing abrasive: Cr,0, powder. Other polishing abrasives with a particle size of 5 μm can also be used. 4.8 Thin film etchant: The volume ratio of supersaturated oxalic acid aqueous solution to hydrofluoric acid (4.3) is 4:1. 4.9 Chemical etchant: 20 mL of ethylene glycol (4.4) plus 15 mL of nitric acid (4.2) plus 10 mL of hydrofluoric acid (4.3) plus 70 mL of deionized water (4.5).
4.10 Mounting resin: The weight ratio of EPOFIX epoxy resin to hardener is 5:1. Other mounting materials can also be used. 5 Instruments and equipment
5.1 Metallographic sample polishing machine: 50~500r/min. 5.2 Muffle furnace, maximum temperature 900℃.
5.3 Reading microscope: magnification 30 times, micrometer graduation value 0.01mm. 5.4 Metallographic microscope: magnification 30~1200 times. 5.5 Macroscopic reproducibility instrument: magnification 0.5~30 times. 5.6 Mounting mold: plastic or stainless steel pipe $25mm×20mm. 6 Inspection method
6.1. Sampling
6.1.1 Upper end plug ring weld and plugging hole weld sample 2
GB/T118091998
Use wire cutting or mechanical processing to take a sample with a length of 18mm, and then cut it along the AA surface (see Figure 3). m
Figure 3 Schematic diagram of sampling of upper end plug sample
6.1.2 Lower end plug ring weld sample
Use wire cutting or mechanical processing to take a sample with a length of 20mm, and then cut it along the BB surface (see Figure 4). B
* Schematic diagram of sampling of the lower end plug sample
6.1.3 Single inspection sample for circumferential weld porosity and bulging Cut the sample along the C-C surface by mechanical processing, and then cut the sample to a length of 20mm (see Figure 5). ~1mml
Figure 5 Schematic diagram of porosity and bulging inspection sample
6.2 Mounting
Melting zone
Grind the sample to be inspected on 180 sandpaper, then clean the sample with alcohol, and clean it with acetone if there is oil stain. After the sample is dry, put it into the mold (5.6) with the ground surface facing down, pour in the mounting resin (4.10), let it stand at room temperature for 12 hours, and take it out after the resin is completely solidified. 6.3 Sample preparation
6.3.1 Sample preparation by thin film etching method
Grind the mounted sample (6.2) on 180~800\ metallographic water-abrasive paper one by one, using water as a lubricant. During the grinding process, attention should be paid to applying force evenly, so that the grinding surface is as parallel to the central axis of the sample as possible. The final grinding surface should be close to coincide with the central axis and be smooth and flat. After grinding, the sample is etched with an etchant (4.8) for about 3 seconds to make the sample present a clear image of the melting zone, and then soaked in tap water for about 3
5 minutes.
6.3.2 Sample preparation by chemical etching
GB/T11809—1998
Grind the mounted sample (6.2) on 180*～800* metallographic water-abrasive paper, then mechanically polish it with Cr20 powder (4.7), and finally chemically polish it with polishing liquid (4.6) until the sample surface is bright and scratch-free. The polished sample is treated with an etchant (4.9) Perform shallow etching. Etching method: soak absorbent cotton in the etchant (4.9), then wipe the sample surface for about 10 seconds.
6.3.3: Preparation of three-zone structure samples of weld
Grind the unmounted sample on 180*～800* metallographic water sandpaper one by one, then mechanically polish with Cr0: powder (4.7), and then chemically polish with polishing liquid (4.6) until there is no scratch on the sample surface and the concave and convex grain structure is observed under the metallographic microscope. The polished sample is placed in a muffle furnace that has been heated to 500℃ and heated for 5 minutes. Take it out and cool it to room temperature in the air. 6.4 Inspection
6.4.1 Measurement of penetration and related parameters
6.4.1.1 Measurement of P ring and P end values
The test surface shall not be wiped after being etched by the thin film etching method. Focus it on the reading microscope with water. After observing the penetration image, rotate the micrometer knob to align the scale to zero, move the sample to make the edge line of the girth weld or the edge of the plugging hole weld coincide with one of the measurement lines, and then rotate the micrometer knob to measure the melting zone depth values ​​P ring and P wall of the girth weld and the plugging hole weld. If necessary, use a macroscopic copy instrument (5.5) to photograph and record the displayed melting zone image. 6.4.1.2 Measurement of penetration S ring and S error
After cleaning and drying the chemically etched sample, use a metallographic microscope to measure the penetration values ​​S abandoned and S of the girth weld and the plugging hole weld. The magnification is greater than 50 times and the measurement data are recorded.
6.4.1.3 Measurement of effective penetration S'
According to the inspection requirements, the effective penetration S' value can be measured. The measurement method of effective penetration S when common defects exist is shown in Appendix A (Standard Appendix).
6.4.2 Inspection of weld defects
For samples prepared by chemical etching and thin film etching, check whether there are cracks, pores, inclusions, bulging and other defects in the melting zone at an appropriate magnification. If there are defects, record the type, size and location of the defects. 6.4.3 Inspection of metallographic structure of three zones of weld
After cooling the sample (6.3.3) oxidized by thermal dyeing, observe the grain structure of the melting zone, heat-affected zone and matrix of the weld with a metallographic microscope and record it by photographing. Photography can be done by bright field or polarized light illumination. The microscopic observation of the three zones of the girth weld and the magnification of the photography are selected according to the grain size. 6.4.4 Single inspection of pores and bulges in girth welds Grind the cut girth weld cross-section specimen on 280\ or 300* metallographic water-abrasive paper, and observe whether there are pores or bulges under a reading microscope every time about 0.2mm is ground off until the entire girth weld melting zone is ground. If there are pores or bulges, measure their size and record their location, and take metallographic photos when necessary.
7 Experimental report and result evaluation
7.1 Experimental report
The experimental report should report the actual measured results of the penetration depth and other measurement parameters, report the defect geometric size and location, and provide typical metallographic photos. 7.2 Result evaluation
The result evaluation should compare the experimental results with the technical conditions agreed upon by the supplier and the user to evaluate whether the inspection sample is qualified. Note d-
a) Incomplete penetration
d) Porosity or inclusions on the end plug side
Porosity at the joining point
Diameter of the pore or inclusion.
GB/T11809—1998
Appendix A
(Appendix to the standard)
Graphic representation of effective penetration value S'
c) Porosity or inclusions on the pipe wall
b) Cracks
e) Bulging
g) Depression on the outer surface
GB/T118091998
h) Gap between end plug and wall
Figure A1 (End)
National Standard of the People's Republic of China
Metallographic Inspection of Welds of Nuclear Fuel Holders of Pressurized Water Reactors
GB/T11809—1998
Published by China Standards Press Edition
No.16, Sanlihebei Street, Fuxingmenwai, Beijing
Postal Code: 100045
Tel: 68522112
Printed by Qinhuangdao Printing Factory of China Standard Press Distributed by Beijing Distribution Office of Xinhua Bookstore Sold by Xinhua Bookstores in all regions Copyright is exclusive and no reproduction is allowed
Format 880×12301/16
Printing sheet 3/4
Number of words 13,000 words
First edition in July 1998
Second printing in July 1998
Print run 1-1000
Book number: 155066·1-15013
Heading 343-402 Result evaluation
Result evaluation should compare the test results with the technical conditions agreed upon by the supplier and the user to evaluate whether the test sample is qualified or not. Note d-
a) Incomplete penetration
d) Porosity or inclusions on the end plug side
Porosity at the joint
Diameter of pores or inclusions.
GB/T11809—1998
Appendix A
(Appendix to the standard)
Graphic representation of effective penetration value S'
c) Porosity or inclusions on the pipe wall
b) Cracks
e) Bulging
g) Depression on the outer surface
GB/T118091998
h) Gap between end plug and wall
Figure A1 (End)
National Standard of the People's Republic of China
Metallographic Inspection of Welds of Nuclear Fuel Holders of Pressurized Water Reactors
GB/T11809—1998
Published by China Standards Press Edition
No.16, Sanlihebei Street, Fuxingmenwai, Beijing
Postal Code: 100045
Tel: 68522112
Printed by Qinhuangdao Printing Factory of China Standard Press Distributed by Beijing Distribution Office of Xinhua Bookstore Sold by Xinhua Bookstores in all regions Copyright is exclusive and no reproduction is allowed
Format 880×12301/16
Printing sheet 3/4
Number of words 13,000 words
First edition in July 1998
Second printing in July 1998
Print run 1-1000
Book number: 155066·1-15013
Heading 343-402 Result evaluation
Result evaluation should compare the test results with the technical conditions agreed upon by the supplier and the user to evaluate whether the test sample is qualified or not. Note d-
a) Incomplete penetration
d) Porosity or inclusions on the end plug side
Porosity at the joint
Diameter of pores or inclusions.
GB/T11809—1998
Appendix A
(Appendix to the standard)
Graphic representation of effective penetration value S'
c) Porosity or inclusions on the pipe wall
b) Cracks
e) Bulging
g) Depression on the outer surface
GB/T118091998
h) Gap between end plug and wall
Figure A1 (End)
National Standard of the People's Republic of China
Metallographic Inspection of Welds of Nuclear Fuel Holders of Pressurized Water Reactors
GB/T11809—1998
Published by China Standards Press Edition
No.16, Sanlihebei Street, Fuxingmenwai, Beijing
Postal Code: 100045
Tel: 68522112
Printed by Qinhuangdao Printing Factory of China Standard Press Distributed by Beijing Distribution Office of Xinhua Bookstore Sold by Xinhua Bookstores in all regions Copyright is exclusive and no reproduction is allowed
Format 880×12301/16
Printing sheet 3/4
Number of words 13,000 words
First edition in July 1998
Second printing in July 1998
Print run 1-1000
Book number: 155066·1-15013
Heading 343-40
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