CN116135401A

CN116135401A - Laser identification method of zirconium alloy cladding tube for nuclear reactor

Info

Publication number: CN116135401A
Application number: CN202111353721.7A
Authority: CN
Inventors: 赵林科; 胡旭坤; 王晨阳; 段俊婷; 商毅龙; 于海慧; 高博; 孙阳平
Original assignee: State Nuclear Bao Ti Zirconium Industry Co
Current assignee: State Nuclear Bao Ti Zirconium Industry Co
Priority date: 2021-11-16
Filing date: 2021-11-16
Publication date: 2023-05-19

Abstract

The invention relates to a laser identification method of a zirconium alloy cladding tube for a nuclear reactor, which comprises the following steps: and (3) processing the surface roughness of the cladding tube, setting laser marking parameters, including laser marking speed, laser marking power, marking bar code and digital code of the cladding tube laser, and detecting marking effect, including measuring thickness measurement of a heat affected zone of a laser marking section of the cladding tube by using a microscope, corrosion test and ultrasonic flaw detection, and finishing laser marking by the qualified cladding tube after the detection. The laser marking method is used for laser marking of the zirconium alloy cladding tube for the nuclear reactor, improves the single-branch tracking traceability of the zirconium alloy cladding tube for the nuclear power, and avoids the problem of nuclear leakage caused by surface damage of the cladding tube due to laser marking.

Description

Laser identification method of zirconium alloy cladding tube for nuclear reactor

Technical Field

The invention relates to the technical field of metal pipe processing, in particular to a laser identification method of a zirconium alloy cladding pipe for a nuclear reactor, which is used for the field of processing of the zirconium alloy cladding pipe required by manufacturing a nuclear fuel assembly for the nuclear reactor.

Background

Nuclear power is an important component of clean energy, and is an important support for realizing the sustainable development targets of carbon peak and carbon neutralization. The third-generation nuclear power technology is the latest requirement for nuclear power development, the fuel assembly of the third-generation nuclear power technology has deeper fuel consumption, and higher requirements are put on the nuclear safety quality, in particular to the technical index requirements of the nuclear safety barrier. Zirconium alloys are cladding materials of nuclear reactors, which directly determine the safety of the nuclear reactor. The third generation nuclear power generally requires that each zirconium alloy cladding tube is loaded with a unique traceability identifier so as to facilitate the quality traceability of the reactor operation process and the quality investigation of the cladding tube after a nuclear leakage accident, and generally requires that the nondestructive inspection result of the cladding tube can be traced through the cladding tube identifier, so that the position where leakage occurs can be rapidly locked, and a technician can accurately formulate a coping strategy. At present, the permanent identification is generally realized by laser engraving a bar code on a cladding tube, the surface of the cladding tube is damaged by the laser engraving of the bar code, the bar code is a weak link in the processing of the cladding tube, and the risk of nuclear fuel leakage exists. Therefore, the cladding tube laser identification needs to adopt a specific identification process, so that the reliability of the cladding tube laser identification is ensured, and meanwhile, the effective identification of the cladding tube is realized.

Disclosure of Invention

In order to solve the technical problems, the invention provides a laser identification method of a zirconium alloy cladding tube for a nuclear reactor, which realizes traceability of the zirconium alloy cladding tube for the nuclear reactor and solves the technical problems of surface damage of the cladding tube caused by laser marking. The laser marking method is used for laser marking of the zirconium alloy cladding tube for the nuclear reactor, improves the single-branch tracking traceability of the zirconium alloy cladding tube for the nuclear power, and avoids the problem of nuclear leakage caused by surface damage of the cladding tube due to laser marking; the method solves the problem that the laser marking of the zirconium alloy cladding tube for the nuclear reactor cannot be independently and autonomously realized in China, initiates the precedent of laser marking of the zirconium alloy cladding tube for the nuclear reactor for autonomous production in China, and gets rid of the situation of being technically restricted by people.

The technical scheme adopted by the invention is as follows: a method of laser marking a zirconium alloy cladding tube for a nuclear reactor, the method comprising:

surface roughness treatment of the cladding tube;

setting laser marking parameters;

cladding tube laser marking, including bar code and digital code;

marking effect detects, includes: measuring the thickness of a heat affected zone, performing corrosion test and performing ultrasonic flaw detection;

the laser marking is finished after the cladding tube which is qualified by the thickness measurement of the heat affected zone, the corrosion test and the ultrasonic flaw detection test;

wherein: the heat affected zone thickness measurement: after laser marking, measuring the thickness of a longitudinal section heat affected zone of a cladding tube laser marking position by using a microscope;

wherein: the corrosion test: cladding tube for intercepting laser marking section is carried out in water vapor successively

And

the surface of the sample is checked after the corrosion test, and the laser marking position of the surface of the sample for the two corrosion tests is a black or gray black oxide film without white or any abnormal corrosion products;

wherein: the ultrasonic flaw detection comprises the following steps: and performing ultrasonic flaw detection on the cladding tube after laser marking.

Preferably, wherein the cladding tube surface roughness treatment is polished using a 600 mesh SiC abrasive belt.

Preferably, the laser marking speed is 200mm/s, and the laser marking power is 10W-25W.

Preferably, the heat affected zone has a thickness of 6 to 30 μm.

Preferably, the water vapor in the corrosion test is water vapor with the temperature of (400+/-3) DEG C and the pressure of (10.3+/-0.7) MPa.

Preferably, wherein the ultrasonic flaw detection: and the ultrasonic flaw detection signal amplitude of the laser marking section is smaller than or equal to 40% of the minimum signal amplitude generated by the standard flaw, and the pipe is qualified.

Preferably, wherein the post-polishing cladding tube surface roughness Ra is less than or equal to 0.8 μm.

Drawings

Fig. 1 is a flow chart of a laser marking process for cladding tubes according to the invention.

Detailed Description

The technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

As shown in fig. 1, a method for identifying a zirconium alloy cladding tube for a nuclear reactor according to an embodiment of the present invention includes:

surface roughness treatment of cladding tube: due to the limit requirement of the nuclear grade zirconium material on contact materials, the cladding tube is polished by using a 600-mesh SiC abrasive belt in the embodiment, and the surface roughness Ra of the cladding tube after polishing is less than or equal to 0.8 mu m. The SiC abrasive belt polishing can not produce abnormal element pollution on the surface of the zirconium alloy pipe, si and C elements can not affect the corrosion resistance of the pipe, 600 mesh abrasive belt polishing can not produce scratches affecting laser marks on the surface of the cladding pipe, and the phenomenon that marks are fuzzy due to the laser marking of the cladding pipe is avoided.

Setting initial laser marking parameters: the laser marking speed is 200mm/s, and the visual readability of the laser mark of the cladding tube can be ensured by using the laser marking speed. Setting initial marking power, laser marking power of 10W-25W, selecting ten cladding tubes with qualified surface polished, and laser marking 3-6 groups of bar codes and 1 group of digital codes at the corresponding positions of each cladding tube. The laser marked area should not have macroscopic defects such as oxidation color, scratches, stains and the like which are visible visually after marking.

Wherein 3-6 groups of bar codes and 1 group of digital codes are respectively carved at equal intervals along the circumference of the cladding tube. Bar codes are translations of digital codes, bar codes and digital equivalents.

The bar code system uses a cross 25 code (with check bits).

The digital code consists of 12-bit Arabic numerals, and the specific coding rule is as follows:

remarks: the specific requirements for the coding are shown in Table 1.

TABLE 1 digital code encoding requirement

The production lot number code, the in-lot sequence number, the material code and the verification code should be separated by a certain interval to facilitate visual reading.

The bar code length is about 25.5mm and adjacent bar code sets are spaced about 1mm apart.

A set of digital codes is engraved axially along the cladding tube at a distance of about 22.5mm from the axial spacing of the bar code. The digital code digits adopt hollow characters, so that the laser contact area during laser marking is reduced, and the digits are clear and distinguishable. The size of the digital code: the length of the digital code is about 38mm, the minimum height is 3mm, the stroke width is 0.25-0.3 mm, and the minimum width of the character is 1mm.

The size requirements of the laser marking bar code and the digital code of the cladding tube are standardized, automatic identification of a code reader on a production line can be realized, the identification accuracy of laser identification can be ensured, and the phenomenon of repeated number and error number caused by code reading identification errors is avoided.

The laser identification bar code can be tracked by single cladding tube of batch-to-batch, each batch of cladding tubes has a unique batch number code, each branch tube in each batch of tubes is endowed with a unique serial number, each cladding tube can be guaranteed to be unique and traceable, and the purpose of single cladding tube tracking is achieved.

Marking effect detection:

after laser marking, extracting the laser marked cladding tube to intercept the cladding tube containing the laser marking section by 90mm, and measuring the thickness of a heat affected zone of the longitudinal section of the cladding tube by using a microscope, wherein the thickness of the heat affected zone is 6-30 mu m. The laser marked areas should not have macroscopic defects such as oxidation, scratches, stains, etc. that are visible to the eye.

The marked cladding tube is extracted, 90mm of the marked cladding tube is taken as a sample, and the sample is processed in water vapor with the temperature of (400+/-3) DEG C and the pressure of (10.3+/-0.7) MPa

The corrosion test of the marking area can test the corrosion resistance of the laser marking area, and the local abnormal corrosion phenomenon of the laser marking area of the cladding tube in the reactor operation process can be effectively avoided through corrosion performance detection, so that the nuclear leakage accident occurs due to the rupture of the oxide film. />

After the corrosion test, the sample surface is checked and then continued +.>

And (3) the surface of the sample is inspected after the corrosion test, and the laser marking positions on the surface of the sample for the two corrosion tests are black or gray black oxide films, and neither white nor any abnormal corrosion products exist.

Confirming laser marking power: and after the thickness measurement of the heat affected zone and the corrosion test of the cladding tube subjected to laser marking are qualified, confirming that the laser marking power is the laser marking power of normal batch production. If the detection is unqualified, resetting the laser marking power, measuring the thickness of a heat affected zone, detecting corrosion test and the like, and performing laser marking test until the detection is qualified, wherein the laser marking power can be determined.

The laser marking laser emission power can be gradually attenuated along with the service life, and the proper cladding tube laser marking power can be dynamically determined by the method, so that the marking process parameters can be dynamically adjusted along with the attenuation of the laser emission power.

Because the emission power of the laser has attenuation effect, the emission power can be gradually attenuated along with the use time, a sample is required to be manufactured before each equipment starts batch marking every day, the thickness of a heat affected zone is measured, the thickness of the heat affected zone is required to be 6-30 mu m, the laser marking operation every day can be started after the thickness of the heat affected zone is detected to be qualified, and the laser marking power is reset after the detection of unqualified laser marking operation is started to be debugged.

The marking parameters can be effectively confirmed by detecting the thickness of the heat affected zone every day, the proper laser marking power of the cladding tube can be dynamically determined, and the marking process parameters can be dynamically adjusted along with the attenuation of the laser emission power.

Cladding tube laser marking: after determining the laser marking power, starting to perform cladding tube laser marking, wherein the laser marking speed is 200mm/s, and 3-6 groups of bar codes and 1 group of digital codes are engraved on each cladding tube.

Ultrasonic flaw detection: and carrying out ultrasonic flaw detection on the cladding tube after laser marking.

The ultrasonic flaw detection signal amplitude is compared by using an ultrasonic flaw detection signal standard value, wherein the ultrasonic flaw detection signal standard value is the amplitude of an ultrasonic flaw detection standard tube standard wound, the standard wound is an artificial U-shaped wound in the longitudinal direction and the transverse direction of the inner surface and the outer surface of a cladding tube, the depth of the ultrasonic flaw detection signal is not more than 0.05mm, the width of the ultrasonic flaw detection signal is 0.10mm plus or minus 0.005mm, and the length of the ultrasonic flaw detection signal is not more than 1.65mm. And (3) aligning the standard damage of the standard tube to the ultrasonic wave during calibration, adjusting the amplitude of the standard damage reflection signal to 100% of the full screen, and comparing the screen display signal during ultrasonic flaw detection of the cladding tube with the amplitude of the standard damage signal to determine whether the cladding tube is qualified or not. And the cladding tube with the amplitude of the ultrasonic flaw detection signal at the laser marking position being smaller than or equal to 40% of the minimum signal amplitude generated by the standard flaw is qualified. And (5) completing laser marking of the qualified flaw detection cladding tube.

And detecting the thickness of the heat affected zone of the marking area, the appearance quality of the marking area and the corrosion performance of the marking area, wherein the detection of the thickness of the heat affected zone of the marking area is 6-30 mu m, so that the laser mark of the cladding tube can be read through a code reader. The appearance quality of the marking area (without macroscopic defects such as oxidation color, scratch, pollution and the like which are visible) can ensure that the cladding tube is prevented from being damaged due to creep in the running process of the nuclear reactor.

The ultrasonic flaw detection after the cladding tube laser marking is adopted to determine the ultrasonic standard flaw size and detection standard of the cladding tube, the ultrasonic detection method can be adopted to effectively find out abnormal nicks generated by the laser marking, waste judgment is carried out on the tube unqualified in ultrasonic detection, and nuclear safety risks caused by the abnormal damages generated on the surface of the cladding tube due to the laser marking are avoided.

The invention discloses an embodiment of a laser identification method for a zirconium alloy cladding tube for a nuclear reactor, which comprises the following steps:

example 1

Step S1: polishing a Zr-4 alloy cladding tube with the diameter of phi 9.5x0.57 mm by using a 600 mesh SiC abrasive belt, wherein the surface roughness of the cladding tube after polishing is 0.42 mu m;

step S2: setting the laser marking speed as 200mm/s and setting the laser marking power as 12W;

step S3: 4 groups of bar codes and 1 group of digital codes are engraved on the circumference of ten cladding tubes;

step S4: and 3 cladding tubes marked by laser are extracted, 90mm of the laser marking section is cut, and the thickness of the heat affected zone of the longitudinal section is measured to be 5 mu m by using a microscope, so that the requirement of 6-30 mu m of the thickness of the heat affected zone cannot be met.

Example 2

Step S1: polishing a Zr-4 alloy cladding tube with the diameter of phi 9.5 multiplied by 0.57mm by using a 600-mesh SiC abrasive belt, wherein the surface roughness of the polished tube is 0.42 mu m;

step S2: setting the laser marking speed as 200mm/s and setting the laser marking power as 20W;

step S4: extracting 3 cladding tubes marked by laser, intercepting 90mm sections containing laser marking areas, and respectively measuring the thickness of a heat affected zone of the longitudinal section of each cladding tube to be 23 mu m by using a microscope, so that the requirements of 6-30 mu m of the thickness of the heat affected zone are met.

Step S5: cutting out the rest 7 marked cladding tubes, taking 90mm of laser marking sections as a sample, carrying out a 72-hour corrosion test on the sample in water vapor with the temperature of (400+/-3) ℃ and the pressure of (10.3+/-0.7) MPa, checking that a slight white corrosion product exists on the surface of the sample after the test, continuing 264-hour corrosion test on the sample, and checking that an obvious white corrosion product exists at the laser marking position on the surface of the sample after the test, so that the corrosion test requirement cannot be met.

Example 3

step S2: setting the laser marking speed as 200mm/s, and initially setting the laser marking power as 16W;

step S3: 4 groups of bar codes and 1 group of digital codes are engraved on the circumference of ten cladding tubes.

Step S4: extracting 3 cladding tubes marked by laser, intercepting 90mm of a section containing the laser marking, and measuring the thickness of a heat affected zone of a longitudinal section to be 16 mu m by using a microscope to meet the requirement of 6-30 mu m of the thickness of the heat affected zone;

step S5: cutting out the rest 7 marked cladding tubes, taking 90mm of laser marking sections as a sample, carrying out a 72-hour corrosion test on the sample in water vapor with the temperature of (400+/-3) ℃ and the pressure of (10.3+/-0.7) MPa, checking that the surface of the sample is gray black after the test, carrying out 264-hour corrosion test on the sample again, checking that the laser marking position of the surface of the sample is still gray black after the test, and detecting the requirement of the corrosion test of the result.

And determining that the laser marking speed is 200mm/s and the laser marking power is 16W according to the steps, and carrying out laser marking on 600 cladding tubes in each batch. 4 groups of bar codes are respectively engraved at equal intervals along the circumferential direction of the cladding tube, the bar codes between the groups are spaced by about 1mm, the width of the bar codes is about 25.5mm, and the spacing distance between the bar codes and the digital codes is about 22.5mm. The digital code digits adopt hollow characters, so that the laser contact area during laser marking is reduced, and the digits are clear and distinguishable. The digital code width is about 38mm, the digital code height is 4mm, the stroke width is 0.28mm, the starting point of the bar code mark is 310mm from the end of the cladding tube, and the batch of bar codes are set as follows: 00088XXXX40Y (XXXXX is the sequence number in the batch, Y is the automatic calculation of the system), and the marked laser mark is visually clear. The batch of pipes are subjected to laser marking operation in two days, the thickness of a heat affected zone is sampled and detected at the beginning of each day, and is 15 mu m and 17 mu m respectively, so that the requirement of 6-30 mu m of the thickness of the heat affected zone is met, and the laser marking operation of the cladding pipe is started after the thickness detection of the heat affected zone is confirmed to be qualified;

step S6: the ultrasonic flaw detection is carried out on the cladding tube of the batch after the laser marking, the standard injury is a manual U-shaped injury in the longitudinal direction and the transverse direction of the inner surface and the outer surface of the tube, the depth is 0.035mm, the width is 0.10mm, and the length is 1.00mm. And in the ultrasonic flaw detection process, waste judgment treatment is carried out on the pipe with the amplitude of the ultrasonic flaw detection signal at the laser marking position exceeding 40% of the minimum signal amplitude generated by the standard flaw. And the cladding pipe which is qualified in flaw detection is the cladding pipe which is finally subjected to laser marking.

The cladding tube laser marking qualification rate of the embodiment 3 reaches 96%, and all the machined cladding tube laser marks are qualified through visual inspection and can be read and have no errors through inspection of a code reader. The product is used by a user, the requirement of the user on single-branch identification tracking of the cladding tube in the nuclear fuel assembly manufacturing production line is met, the assembled fuel assembly has no occurrence of local abnormal corrosion and cracking event in a laser marking area in the nuclear reactor operation process, and the quality of the product is approved by the user.

The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims

1. A method of laser marking a zirconium alloy cladding tube for a nuclear reactor, the method comprising:

surface roughness treatment of the cladding tube;

setting laser marking parameters;

cladding tube laser marking, including bar code and digital code;

wherein: the heat affected zone thickness measurement: after laser marking, measuring the thickness of a heat affected zone of the longitudinal section of the cladding tube laser marking section by using a microscope;

And->

2. A method of laser marking a zirconium alloy cladding for a nuclear reactor as claimed in claim 1, wherein the cladding roughness treatment is polished using a 600 mesh SiC abrasive belt.

3. The method of laser marking a zirconium alloy cladding for a nuclear reactor according to claim 1, wherein the setting of the laser marking parameters: the laser marking speed is 200mm/s, and the laser marking power is 10W-25W.

4. A method of laser marking zirconium alloy cladding tubes for nuclear reactors as claimed in claim 1 wherein the heat affected zone thickness is from 6 to 30 μm.

5. The method of laser marking a zirconium alloy cladding for a nuclear reactor as claimed in claim 1, wherein the water vapor for the corrosion test is water vapor at a pressure of (10.3 ± 0.7) MPa at a temperature of (400 ± 3).

6. The method for laser identification of zirconium alloy cladding for nuclear reactor according to claim 1, wherein the ultrasonic flaw detection: and the ultrasonic flaw detection signal amplitude of the laser marking section is smaller than or equal to 40% of the minimum signal amplitude generated by the standard flaw, and the pipe is qualified.

7. A method of laser marking a zirconium alloy cladding for a nuclear reactor as claimed in claim 2, wherein the polished cladding has a surface roughness Ra of less than or equal to 0.8 μm.