Method for manufacturing coated nuclear reactor components with markings

Abstract

The manufacturing method enables the production of nuclear reactor components comprising a substrate (4) and a coating (8) covering a surface (4A) of the substrate. The manufacturing method includes laser marking a pattern (6) on the surface (4A) of the substrate (4) in such a way as to form hollow protrusions (10) of the pattern (6) on the surface (4A) of the substrate (4), and then applying the coating (8) over the pattern (6) onto the surface (4A) of the substrate (4).

Description

Technical Field

[0001] This invention relates to the field of manufacturing nuclear reactor components, particularly nuclear fuel rods. Background Technology

[0002] During the manufacturing of nuclear reactor components, traceability must be ensured in order to identify the source of any potential failure.

[0003] Nuclear fuel assemblies used in nuclear reactors typically consist of bundles of nuclear fuel rods, each fuel rod comprising a cladding that contains nuclear fuel, the cladding being formed by tubes sealed at both ends by plugs.

[0004] The cladding tubes for nuclear fuel rods can be formed from a tubular substrate whose outer surface is coated to protect the substrate from the particularly hazardous environment inside the nuclear reactor.

[0005] To ensure the traceability of nuclear fuel rod cladding tubes, the substrate can be laser-marked, allowing individual identification codes to be printed on the substrate through oxidation.

[0006] However, coloring achieved through laser marking is often accompanied by substrate oxidation, which can lead to substrate weakening and consequently weakening of nuclear fuel rods.

[0007] Furthermore, when the coating subsequently applied to the substrate is opaque, the application of the protective coating can obscure the markings made by coloring the substrate, as is the case with metallic coatings.

[0008] To allow for traceability of the cladding tube throughout the manufacturing process of the nuclear fuel rod, a separate identification code can be marked on the sacrificial end of the substrate, the substrate can be coated without coating the sacrificial end, a separate identification code can be marked on the coated portion of the tube, and then the sacrificial portion of the substrate can be cut off.

[0009] However, this requires additional cutting of the sacrificial portion and marking of the substrate, and there is still a risk of errors, especially the risk of mismatch between the individual identification code on the sacrificial portion of the substrate before coating and the individual identification code on the coating on the substrate. Summary of the Invention

[0010] One of the objectives of this invention is to provide a method for manufacturing marked nuclear reactor components, such as nuclear fuel rods, which is easy to implement and provides traceability in a reliable and easy manner.

[0011] Therefore, the present invention provides a method for manufacturing a nuclear reactor component, the nuclear reactor component comprising a substrate and a coating covering the surface of the substrate, the manufacturing method comprising: laser marking a pattern on the surface of the substrate, and then applying a coating over the pattern on the surface of the substrate, the marking being performed in a manner that forms a recessed pattern, the recessed pattern drawing the pattern in the surface of the substrate.

[0012] In a particular implementation, the manufacturing method includes one or more of the following optional features:

[0013] - The markings are made in a way that the pattern is readable before and after the coating is applied;

[0014] - The depth of the recessed pattern is less than 5μm;

[0015] - The pattern includes at least a series of lines that draw readable identification codes, each line consisting of multiple dots and / or dashed lines;

[0016] - The pattern includes at least one code, such as a bar code, a matrix code, and / or an alphanumeric code;

[0017] - Laser marking is performed via pulses, preferably with a pulse frequency between 5kHz and 2MHz, a power between 18W and 22W, and a pulse width of 200×10. -15 s and 50×10 -12 The scanning speed is between 200 mm / s and / or between 200 mm / s to achieve sufficient morphological contrast to ensure the readability of the pattern before and after the coating is applied;

[0018] - The substrate is metallic;

[0019] -The substrate is made of zirconium-based material;

[0020] - The coating is either metallic or an oxide;

[0021] - The coating is made of chromium-based materials;

[0022] - The coating is made of oxides, such as oxides of the ZrO2 or CrO2 type;

[0023] - Nuclear reactor components are tubes, the base has a tubular shape, and the surface marked with patterns and covered by a coating is the outer surface of the tubular base;

[0024] - Nuclear reactor components are cladding tubes, such as nuclear fuel rod cladding tubes or control rod cladding tubes. Attached Figure Description

[0025] The invention and its advantages will become apparent from the following description, which is given by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0026] Figure 1 The step of marking the surface of the substrate of the nuclear reactor component during a manufacturing process for the component is shown;

[0027] Figure 2 The steps for automatically reading the marks performed during the manufacturing process are shown;

[0028] Figure 3 The steps of applying a coating to a marked substrate, performed during the manufacturing process, are illustrated.

[0029] Figure 4 The steps for automatically reading the marks performed during the manufacturing process are shown;

[0030] Figure 5 The previous view shows a portion of the markings formed during the marking step;

[0031] Figure 6 It shows along Figure 5 The surface profile of the marked surface is intercepted by line VV;

[0032] Figure 7 It has the ability to pass Figures 1 to 4 A cross-sectional view of a nuclear fuel rod in a cladding tube obtained by the manufacturing method shown. Detailed Implementation

[0033] Figures 1 to 4 A method for manufacturing a nuclear reactor component 2 is shown, the nuclear reactor component 2 including a substrate 4 having a coating 8, the method comprising, in sequence:

[0034] - The step of laser marking the substrate 4 includes marking pattern 6 on surface 4A of the substrate 4. Figure 1 ),

[0035] -Optionally, at least one step of pattern 6 is automatically read ( Figure 2 ),

[0036] - The step of applying coating 8 to surface 4A of substrate 4, coating 8 covering pattern 6 ( Figure 3 ),as well as

[0037] -Optionally, after applying coating 8 ( Figure 4 Then, the steps for automatically reading pattern 6 will be completed.

[0038] The marking of pattern 6 and the application of coating 8 are carried out in the following manner: pattern 6 is applied before coating 8 is applied ( Figure 2 ) and after applying coating 8 ( Figure 4 It is readable, preferably automatically readable.

[0039] Pattern 6 is, for example, a separate identification code used to ensure the traceability of core component 2. Thus, pattern 6 marked on substrate 4 before coating 8 is applied is readable to identify uncoated substrate 4 before coating 8 is applied, and is readable after coating 8 is applied to identify substrate 4 after coating 8 has been applied.

[0040] The markings in pattern 6 are done in a way that locally increases the roughness of surface 4A of substrate 4.

[0041] The marking is done in the form of a recessed pattern 10 and an optional protruding pattern 12 formed on the surface 4A of the base 4.

[0042] Therefore, the marking is performed in such a way that pattern 6 can be read before and after the application of coating 8 by means of morphological contrast.

[0043] The term "morphological contrast" refers to the fact that the recessed pattern 10 and the optional protruding pattern 12 generated by the marking have surfaces with different orientations. These different orientations cause a difference in contrast, thereby allowing the reading of pattern 6, especially by automatic reading.

[0044] The substrate 4 is, for example, a metal substrate, that is, a substrate 4 made of a metal material.

[0045] The substrate 4 is made of, for example, zirconium-based material.

[0046] In this context, zirconium-based materials refer to pure zirconium materials or zirconium-based alloys.

[0047] Pure zirconium material is a material containing at least 99% zirconium by weight. Zirconium-based alloy is an alloy containing at least 95% zirconium by weight.

[0048] In one embodiment, the zirconium-based material of the substrate 6 is a zirconium-based alloy containing 0.8% to 1.8% niobium, 0.2% to 0.6% tin and 0.02% to 0.4% iron by weight, with the balance being zirconium and unavoidable impurities.

[0049] The substrate 4 may be tubular in shape, and the surface 4A marked in the marking step is the outer surface of the tubular substrate 4. Depending on the nuclear reactor components, the substrate 4 may have another shape, such as a plate shape.

[0050] The marking process is performed automatically using a laser marking machine 14, which includes a laser 16. Figure 1 Laser 16 is adapted to generate a laser beam 18 that is directed onto a surface 4A on which pattern 6 is to be marked.

[0051] In a known manner, the laser marking machine 14 is configured to move the laser beam 18 relative to the substrate 4 in order to mark the surface 4A, thereby forming a pattern 6.

[0052] The laser marking machine 14 is configured, for example, to move the laser beam 18 while the substrate 4 remains stationary, or to move the substrate 4 while the laser beam 18 remains stationary, or to move both the laser beam 18 and the substrate 4 such that they move relative to each other.

[0053] In one embodiment, laser marking is performed by pulses, wherein the pulse frequency and parameters are defined to achieve morphological contrast sufficient to ensure the readability of pattern 6 before and after the application of coating 8 (preferably automatically).

[0054] In one implementation, a pulse frequency between 5 kHz and 2 MHz, a laser power between 18 W and 22 W, and a laser size of 200 × 10⁻⁶ are used. -15 s and 50×10 -12 Laser marking is performed using pulse widths between 200 mm / s and / or scanning speeds between 200 mm / s and 2000 mm / s.

[0055] In particular, when these parameters are considered together, compliance with each of these parameters can produce appropriate markings that form recessed and / or raised patterns that allow the markings to be read before and after the application of coating 8.

[0056] Pattern 6 is, for example, a unique identification code, that is, a unique code that identifies substrate 4 and distinguishes it from other substrates. The laser marker 14 is configured to mark a specific code on each substrate 4, which varies depending on the substrate.

[0057] For example, pattern 6 includes barcodes, matrix codes, and / or alphanumeric codes. Matrix codes are, for example, QR codes.

[0058] In a particular embodiment, pattern 6 includes barcodes, i.e., codes formed by multiple parallel bars. The encoding is a result of the number of bars, the width of the bars, and / or the spacing between the bars.

[0059] In one implementation, such as Figure 5 As shown, it illustrates an uncoated substrate 4 marked with pattern 6, which includes at least one line 20.

[0060] Each line 20 is, for example, a continuous line or a line formed by dots and / or dashed lines, particularly a line formed by the alignment of points 22, such as Figure 5 As shown.

[0061] The line 20 formed by the alignment of points 22 is formed, for example, by a pulse-generated laser beam 18, each point 22 being formed by a corresponding pulse, the laser beam 18 being moved relative to the substrate 4 to form the next point 22 with the next pulse.

[0062] The markings of line 20 formed by the alignment of point 22 can control the markings of base 4, especially the depth of the recessed patterns generated by the markings and the height of any protruding patterns generated by the markings.

[0063] In a known manner, thicker or thinner characters for alphanumeric codes can be formed by using lines (thin character elements) or several adjacent parallel lines (thick character elements) to form each element (bars, legs, bars, etc.) of the character.

[0064] Similarly, wider or narrower bars of barcodes can be formed by using a single line (narrow bar) or several adjacent parallel lines (medium or wide bars) to form each bar.

[0065] The present invention enables line 20 to be formed by the alignment of points 22 in order to produce the necessary dashed lines or characters with the thickness and width as described above.

[0066] like Figure 5 As shown, this illustrates a portion of a barcode, where each bar 23 is defined by a line 20 defining a narrow bar 23 or by multiple adjacent lines 20 defining a wide bar. The more lines 20 in a bar 23, the wider the bar 23.

[0067] Figure 5 From left to right, we show a wide stripe 23 formed by three lines 20, a thin stripe 23 formed by one line 20, a wide stripe 23 formed by three lines 20, and a medium stripe 23 formed by two lines 20.

[0068] Figure 6 It is along Figure 5 The surface profile of surface 4A in line VV shows the depth / height of the recessed / protruding pattern on the X-axis.

[0069] For example, marking is performed by generating a recessed pattern 10 with a depth of less than 5 μm.

[0070] Preferably, the marking is done in a manner that creates a recessed pattern 10 with a depth suitable for the thickness of the coating 8 to be applied later.

[0071] Measure the depth of the base pattern from surface 4A in the area unaffected by the markings.

[0072] These parameters allow for obtaining a readable pattern 6 before and after applying coating 8, while preserving the substrate 4.

[0073] Preferably, the height of the raised pattern 12 generated by the marking is less than 10 μm.

[0074] The protruding pattern 12 is generated from the material present at the location of the recessed pattern 10.

[0075] Recessed markings can produce raised markings, which are not as wide as the recessed markings, but are higher than the recessed markings.

[0076] The presence of protruding patterns whose height exceeds the depth of the recessed patterns is not a problem, especially for the strength of base 4.

[0077] like Figure 6 As shown, each point 22 has a central region formed by a central recessed pattern 10 and an optional peripheral region formed by an annular protruding pattern 12 surrounding the central region. Each point 22 may also optionally include additional protruding patterns 12 substantially at the center of the central region, such as... Figure 6 As shown by the dashed line in the image.

[0078] Advantageously, marking is performed in such a way that recessed patterns with a depth greater than the roughness of the surface 4A of the substrate 4 before marking are generated, and / or protruding patterns with a height greater than the roughness of the surface 4A of the substrate 4 before marking are generated.

[0079] Therefore, the area of ​​surface 4A of the substrate 4 with pattern 6 has a greater roughness than the rest of surface 4A of the substrate 4.

[0080] In one example, the surface roughness of surface 4A before marking was between 0.1 micrometers and 0.3 micrometers. Measurements were taken, for example, using a roughness meter or a profilometer.

[0081] Coating steps ( Figure 3 The process is automated using a coating machine (not shown).

[0082] In one exemplary embodiment, the thickness of coating 8 is between 5 μm and 25 μm.

[0083] Coating 8 is made of, for example, a chromium-based material.

[0084] In this context, chromium-based materials refer to pure chromium materials or chromium alloys.

[0085] Pure chromium materials are materials containing at least 99% chromium by weight. Chromium-based alloys are alloys containing at least 85% chromium by weight.

[0086] In one embodiment, the chromium-based material is a chromium-based alloy selected from binary chromium-aluminum (CrAl) alloys, binary chromium-nitrogen (CrN) alloys, and binary chromium-titanium (CrTi) alloys.

[0087] The morphological contrast achieved on substrate 4 must be sufficient to maintain the contrast required for reading pattern 6 when coating 8 is applied (e.g., by physical vapor deposition, particularly by sputtered physical vapor deposition, and even more specifically by magnetron sputtered physical vapor deposition).

[0088] like Figure 3 As shown, after the coating 8 is applied, the free surface 8A of the coating 8 has a corresponding recessed pattern 10A at the recessed pattern 10, and, where appropriate, a corresponding protruding pattern 12A at the protruding pattern 12.

[0089] Therefore, pattern 6 remains readable after coating 8 is applied.

[0090] Each automatic reading step ( Figure 2 and Figure 4 For example, this can be done by means of an automatic reader 24, which includes a reader head 26 and a data processing unit 28, which is configured to read pattern 6, and in particular to decode pattern 6 when pattern 6 is a code.

[0091] The reader 26 is, for example, an image capturing device, such as a camera or still camera, in which case the data processing unit 28 is configured to read the pattern 6 through image analysis. Alternatively, the reader 24 is a scanner.

[0092] Reading Pattern 6 after the marking step ensures that Pattern 6 is readable before continuing the manufacturing process and / or ensures the traceability of the part after marking.

[0093] Reading pattern 6 before coating step 8 allows for the identification of substrate 4 before coating 8 is applied.

[0094] In one embodiment, the manufacturing method includes a machine reading step performed at the end of the marking step to ensure that the pattern 6 is readable before the marked substrate is stored and / or transferred to the coating machine, and a machine reading step performed before the marked substrate 4 enters the coating machine 8 to identify the substrate 4 before the coating 8 is applied and to ensure traceability during the manufacturing method.

[0095] Reading pattern 6 after coating step 8 ensures that pattern 6 is readable after coating 8 has been applied and before the manufacturing process continues, and / or ensures the traceability of substrate 4 of nuclear reactor component 2 after coating 8 is applied, provided that pattern 6 (e.g., a separate identification code) allows for traceability.

[0096] An automatic reader 24 can be provided for reading after marking, and another automatic reader 24 can be provided for reading before applying the coating 8.

[0097] The present invention enables the easy and reliable manufacture of nuclear reactor components, ensuring traceability during the manufacturing process, because pattern 6 is, for example, a separate identification code.

[0098] Only one marking operation is required, which allows pattern 6 to be read before and after the coating is applied.

[0099] The marking operation will not adversely affect the substrate 4 of the nuclear reactor component, and therefore will not affect the structural strength of the nuclear reactor component.

[0100] This invention is not limited to the embodiments described above, as other embodiments are also possible.

[0101] In one example, the substrate 4 is metallic, particularly made of zirconium-based material, and the coating 8 is metallic, particularly made of chromium-based material.

[0102] Alternatively, the substrate 4 may be made of a non-metallic material, such as a composite material comprising a fiber-reinforced matrix (e.g., carbon fiber).

[0103] Alternatively, coating 8 is made of non-metallic materials, particularly oxides, such as oxides of the ZrO2, CrO2, etc.

[0104] Oxides can provide effective protection, especially on metal substrates.

[0105] The metal substrate 4 can be combined with a metal coating or a non-metal coating, or the non-metal substrate 4 can be combined with a metal coating 8 or a non-metal coating 8.

[0106] Figure 7 Nuclear fuel rod 30 is shown, which is intended for use in light water reactors, particularly pressurized water reactors (PWRs) or boiling water reactors (BWRs), VVER reactors, RMBK reactors or heavy water reactors, such as CANDU.

[0107] The nuclear fuel rod 32 has the shape of an elongated rod along the central axis A.

[0108] The nuclear fuel rod 32 includes a cladding 34 for containing nuclear fuel. The cladding 34 includes a tube 36, each end of which has a plug 38 welded to it. The tube 36 extends along the central axis A of the nuclear fuel rod 32.

[0109] Pipe 36 is based on Figures 1 to 6 Nuclear reactor components manufactured using the method shown.

[0110] Therefore, tube 36 includes a tubular substrate 4 coated with coating 8, the substrate 4 being marked with pattern 6 before coating 8 is applied, and then coating 8 is applied to pattern 6, which remains readable after coating 8 is applied.

[0111] For example, a method for manufacturing nuclear fuel rod 32 includes: according to Figures 1 to 6 The manufacturing method shown produces a tube 36 having its pattern 6, then nuclear fuel is inserted into the tube 36 and the tube 36 is sealed with a plug 38.

[0112] Nuclear reactor components are not necessarily the cladding tubes for nuclear fuel rods. Other nuclear reactor components can be manufactured.

[0113] Specifically, control rod cladding tubes can be manufactured. Control rods are designed to be inserted into the core of a nuclear reactor to control its reactivity. Control rods differ from nuclear fuel rods in that they contain neutron-absorbing material instead of nuclear fuel.

[0114] Reactor components do not necessarily have to be tubular. They can have another form.

[0115] In particular, plate-shaped nuclear reactor components can be manufactured. Such components are, for example, nuclear fuel cladding plates, to form plate-shaped nuclear fuel elements comprising nuclear fuel sandwiched between two cladding plates. These nuclear fuel elements are used, for example, in experimental nuclear reactors.

[0116] Pattern 6 is not necessarily a code, especially not a standalone identification code. Pattern 6 can be a simple business mark or a code that identifies the product type.

Claims

1. A method for manufacturing a component for a nuclear reactor, the component comprising a substrate (4) and a coating (8) covering a surface (4A) of the substrate, the method comprising: A pattern (6) is laser-marked on the surface (4A) of the substrate (4), and then a coating (8) is applied over the pattern (6) to the surface (4A) of the substrate (4). The marking is done in a manner that forms a recessed pattern (10) that draws the pattern (6) into the surface (4A) of the substrate (4). The coating (8) is made of pure chromium material containing at least 99% chromium by weight or a chromium-based alloy containing at least 85% chromium by weight. The depth of the laser marking is less than the thickness of the coating.

2. The manufacturing method according to claim 1, wherein, The markings are made in a manner that the pattern (6) is readable before and after the coating (8) is applied.

3. The manufacturing method according to claim 1 or 2, wherein, The depth of the recessed pattern (10) is less than 5 μm.

4. The manufacturing method according to claim 1, wherein, The pattern (6) includes at least a series of lines that draw readable identification codes, each line being formed by multiple dots and / or dashed lines.

5. The manufacturing method according to claim 1, wherein, The pattern (6) includes at least one code.

6. The manufacturing method according to claim 1, wherein, The pattern (6) includes barcodes, matrix codes, and / or alphanumeric codes.

7. The manufacturing method according to claim 1, wherein, The laser marking is performed via pulses.

8. The manufacturing method according to claim 7, wherein, The laser marking operates at a pulse frequency between 5 kHz and 2 MHz, a power between 18 W and 22 W, and a resolution of 200 × 10⁻⁶. -15 s and 50×10 -12 The pulse width is between s and / or the scanning speed is between 200 mm / s and 2000 mm / s to achieve sufficient morphological contrast to ensure the readability of the pattern (6) before and after the coating (8) is applied.

9. The manufacturing method according to claim 1, wherein, The substrate (4) is metallic.

10. The manufacturing method according to claim 9, wherein, The substrate (4) is made of zirconium-based material.

11. The manufacturing method according to claim 10, wherein, The zirconium-based material is a pure zirconium material or a zirconium-based alloy. The pure zirconium material is a material containing at least 99% zirconium by weight, and the zirconium-based alloy is an alloy containing at least 95% zirconium by weight.

12. The manufacturing method according to claim 1, wherein, The thickness of the coating (8) is between 5 μm and 25 μm.

13. The manufacturing method according to claim 1, wherein, The marking is also done in a way that forms a prominent pattern (12).

14. The manufacturing method according to claim 1, wherein, The nuclear reactor component is a tube, the substrate (4) has a tubular shape, and the surface (4A) marked with the pattern (6) and covered by the coating (8) is the outer surface of the tubular substrate (4).

15. The manufacturing method according to claim 1, wherein, The nuclear reactor component is a cladding tube.

16. The manufacturing method according to claim 1, wherein, The nuclear reactor components are nuclear fuel rod cladding tubes or control rod cladding tubes.

17. The manufacturing method according to claim 13, wherein, The height of the protruding pattern is greater than the surface roughness of the substrate before marking.

18. The manufacturing method according to claim 13, wherein, The height of the protruding pattern is less than 10 μm.

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