A zirconium alloy cladding for nuclear power reactor accident tolerant fuel and a method of manufacturing the same

Abstract

The application discloses a zirconium alloy cladding for nuclear power reaction accident fault-tolerant fuel and a preparation method thereof. The zirconium alloy cladding for nuclear power reaction accident fault-tolerant fuel comprises a zirconium alloy base material, and a zirconium oxide bottom film layer and an aluminum-zirconium mixed film layer are sequentially arranged on the surface of the zirconium alloy base material. The zirconium alloy cladding for nuclear power reaction accident fault-tolerant fuel has excellent interface bonding between layers, uniform thickness of each layer, compact structure, and finally has good corrosion resistance, wear resistance and high-temperature water vapor corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of zirconium alloy cladding technology for fault-tolerant fuel in nuclear power plant reactor accidents, and particularly to a zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents and its preparation method. Background Technology

[0002] Zirconium alloy cladding is a key material used in nuclear power reactor cores, often referred to as the "first line of defense" in nuclear reactors. Its stable performance and extended lifespan are crucial for ensuring the safety and reliability of the reactor core. Accident-tolerant fuels (ATFs) are a new generation of nuclear fuels actively developed by countries worldwide. Applying a protective coating to the zirconium alloy cladding, providing resistance to high-temperature oxidation and water vapor corrosion, can reduce water-side corrosion and hydrogen production, achieving wear resistance, corrosion prevention, and extended lifespan. The design of accident-tolerant cladding protective coatings must comprehensively consider factors such as the material's mechanical properties, resistance to high-temperature oxidation (corrosion), low neutron absorption cross-section, and minimal reaction with fission products. Among the many materials, oxidation-resistant stainless steel (FeCrAl), heat-resistant alloys (Mo, Nb, Cr, etc.), MAX phase ceramics (Ti3AlC2, Ti2AlC, Nb2AlC, etc.), oxide ceramics (ZrO2, SiO2, Cr2O3), and carbide ceramics (SiC, ZrC) have all been considered as candidate coating materials for reactor cladding due to their respective performance characteristics. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reaction accidents, which has excellent interfacial bonding between layers, uniform thickness of each layer and dense structure, and ultimately has good anti-corrosion and wear resistance as well as high-temperature water vapor corrosion resistance.

[0004] The technical problem to be solved by the present invention is to provide a method for preparing zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reaction accidents. This method does not require the introduction of a metal transition layer, but directly generates an oxide ceramic layer in situ on the surface of the zirconium alloy substrate. This method does not reduce the absorption efficiency of nuclear fuel for neutrons and does not contaminate the nuclear fuel reaction system.

[0005] To address the aforementioned technical problems, the present invention provides a zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents, comprising a zirconium alloy substrate, wherein a zirconium oxide base film layer and an alumina-zirconium mixed film layer are sequentially disposed on the surface of the zirconium alloy substrate.

[0006] In one embodiment, the thickness of the zirconium oxide substrate is 2 μm to 6 μm.

[0007] In one embodiment, the thickness of the alumina-zirconium hybrid film is 10 μm to 50 μm.

[0008] To address the aforementioned technical problems, this invention provides a method for preparing a zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents, comprising the following steps:

[0009] A first plasma electrolytic oxidation treatment is performed on a zirconium alloy substrate to generate a zirconium oxide substrate layer in situ on the surface of the zirconium alloy substrate, thereby obtaining a first zirconium alloy treated part.

[0010] The first zirconium alloy part is subjected to a second plasma electrolytic oxidation treatment to generate an in-situ alumina-zirconium mixed film layer on the surface of the first zirconium alloy part, thus obtaining the finished product.

[0011] In one embodiment, in the first plasma electrolytic oxidation treatment, an anodic unidirectional pulse treatment is used to generate a zirconium oxide substrate layer in situ on the surface of the zirconium alloy workpiece.

[0012] In one embodiment, the power supply parameters for the unidirectional pulse processing of the anode are: forward voltage 200V to 250V, duty cycle 25% to 45%, pulse frequency 100Hz to 1000Hz, and processing time 5min to 30min.

[0013] In one embodiment, in the second plasma electrolytic oxidation treatment, a bidirectional pulse treatment with cathode and anode is used to generate an in-situ alumina-zirconium mixed film on the surface of the first zirconium alloy part.

[0014] In one embodiment, the power supply parameters for the bidirectional pulse processing of the cathode and anode are: positive voltage 200V~250V, duty cycle 30%~60%, pulse frequency 100Hz~1000Hz, negative voltage 50V~80V, duty cycle 20%~30%, pulse frequency 100Hz~1000Hz, and processing time 5min~30min.

[0015] In one embodiment, the electrolyte used in the first or second plasma electrolytic oxidation treatment includes: sodium polyphosphate 10 g / L to 30 g / L, sodium silicate 10 g / L to 40 g / L, sodium aluminate 10 g / L to 30 g / L, sodium oxalate 5 g / L to 30 g / L, sodium hydroxide 2 g / L to 10 g / L, and disodium ethylenediaminetetraacetate 2 g / L to 10 g / L.

[0016] In one embodiment, the temperature of the bath solution in the first plasma electrolytic oxidation treatment or the second plasma electrolytic oxidation treatment is controlled at 25°C to 50°C.

[0017] Implementing this invention has the following beneficial effects:

[0018] The present invention provides a zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents, comprising a zirconium alloy substrate, on the surface of which a zirconium oxide base film layer and an alumina-zirconium mixed film layer are sequentially disposed. The interfacial bonding between the zirconium alloy substrate and the zirconium oxide base film layer, and between the zirconium oxide base film layer and the alumina-zirconium mixed film layer, is excellent. Each layer has uniform thickness and a dense structure, ultimately exhibiting good corrosion resistance, wear resistance, and resistance to high-temperature water vapor corrosion.

[0019] The method for preparing zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactions provided by this invention does not require the introduction of a metal transition layer. Instead, an oxide ceramic layer is directly generated in situ on the surface of the zirconium alloy substrate. This method does not reduce the neutron absorption efficiency of the nuclear fuel and does not contaminate the nuclear fuel reaction system. Detailed Implementation

[0020] Figure 1 This is a surface SEM image of the zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents obtained in Example 1 of the present invention;

[0021] Figure 2 This is a cross-sectional SEM image of the first zirconium alloy processed part obtained in Embodiment 1 of the present invention;

[0022] Figure 3 This is a cross-sectional SEM image of the zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents obtained in Embodiment 1 of the present invention.

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below.

[0024] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0025] In this invention, "preferred" is merely a description of a more effective implementation method or embodiment, and should be understood as not constituting a limitation on the scope of protection of this invention.

[0026] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0027] In this invention, numerical ranges are involved, and unless otherwise specified, they include the two endpoints of the numerical range.

[0028] To address the aforementioned problems, the present invention provides a zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents. The zirconium alloy cladding includes a zirconium alloy substrate, on the surface of which a zirconium oxide base film layer and an alumina-zirconium mixed film layer are sequentially disposed.

[0029] The present invention provides a zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents, comprising a zirconium alloy substrate, on the surface of which a zirconium oxide base film layer and an alumina-zirconium mixed film layer are sequentially disposed. The interfacial bonding between the zirconium alloy substrate and the zirconium oxide base film layer, and between the zirconium oxide base film layer and the alumina-zirconium mixed film layer, is excellent. Each layer has uniform thickness and a dense structure, ultimately exhibiting good corrosion resistance, wear resistance, and resistance to high-temperature water vapor corrosion.

[0030] Specifically, the zirconium oxide coating has the closest elemental composition to the zirconium alloy cladding, a low neutron absorption cross section, and does not affect nuclear fuel release efficiency. It can significantly suppress water vapor corrosion rate and hydrogen generation rate under high-temperature conditions, making it a good protective coating for accident-tolerant zirconium alloy cladding, and exhibiting good physical and chemical compatibility. In one embodiment, the thickness of the zirconium oxide base film is 2 μm to 6 μm.

[0031] Furthermore, the alumina-zirconium mixed film layer is applied to the zirconia base film layer, which further improves the high-temperature performance, chemical stability, and mechanical properties of the finished product, effectively enhancing the safety and economy of the reactor. First, the alumina-zirconium mixed film layer has a high melting point and evaporation temperature, maintaining its structural integrity at high temperatures and effectively preventing further melting and dissolution. Second, the alumina-zirconium mixed film layer has high thermal conductivity, rapidly transferring heat from the nuclear fuel to the coolant, effectively controlling the nuclear fuel temperature and preventing fuel burnout and failure. Third, the alumina-zirconium mixed film layer exhibits good chemical stability under high temperature and irradiation conditions, effectively resisting oxidation and corrosion on the nuclear fuel surface, thus extending the nuclear fuel lifespan. Fourth, the alumina-zirconium mixed film layer has high density, allowing for the storage of more fuel in the same volume, thereby improving the reactor's energy production efficiency. Finally, the alumina-zirconium mixed film layer has low hydrogen absorption under high temperature and irradiation conditions, meaning it does not absorb excessive hydrogen, thus preventing pressure buildup and explosions within the nuclear fuel. In one embodiment, the thickness of the alumina-zirconium hybrid film is 10 μm to 50 μm.

[0032] Accordingly, the present invention provides a method for preparing a zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents, comprising the following steps:

[0033] A first plasma electrolytic oxidation treatment is performed on a zirconium alloy substrate to generate a zirconium oxide substrate layer in situ on the surface of the zirconium alloy substrate, thereby obtaining a first zirconium alloy treated part.

[0034] The first zirconium alloy part is subjected to a second plasma electrolytic oxidation treatment to generate an in-situ alumina-zirconium mixed film layer on the surface of the first zirconium alloy part, thus obtaining the finished product.

[0035] The method for preparing zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactions provided by this invention does not require the introduction of a metal transition layer. Instead, an oxide ceramic layer is directly generated in situ on the surface of the zirconium alloy substrate. This method does not reduce the neutron absorption efficiency of the nuclear fuel and does not contaminate the nuclear fuel reaction system.

[0036] In one embodiment, in the first plasma electrolytic oxidation treatment, an anodic unidirectional pulse treatment is used to generate a zirconia substrate layer in situ on the surface of the zirconium alloy workpiece. Preferably, the power supply parameters for the anodic unidirectional pulse treatment are: forward voltage of 200V to 250V, duty cycle of 25% to 45%, pulse frequency of 100Hz to 1000Hz, and treatment time of 5min to 30min. Under the above conditions, a zirconia substrate layer with excellent interfacial bonding between the zirconium alloy substrate and the zirconia substrate layer, uniform thickness, dense structure, and ultimately good corrosion resistance, wear resistance, and resistance to high-temperature water vapor corrosion can be obtained.

[0037] In one embodiment, during the second plasma electrolytic oxidation treatment, a bidirectional pulsed cathode and anodic treatment is used to generate an in-situ alumina-zirconium mixed film on the surface of the first zirconium alloy workpiece. Preferably, the power supply parameters for the bidirectional pulsed cathode and anodic treatment are: positive voltage of 200V–250V, duty cycle of 30%–60%, pulse frequency of 100Hz–1000Hz; negative voltage of 50V–80V, duty cycle of 20%–30%, pulse frequency of 100Hz–1000Hz; and treatment time of 5min–30min. Under these conditions, an alumina-zirconium mixed film with excellent interfacial bonding between the zirconium oxide substrate and the alumina-zirconium mixed film, uniform thickness, dense structure, and ultimately good corrosion resistance, wear resistance, and resistance to high-temperature water vapor corrosion can be obtained.

[0038] In one embodiment, the electrolyte used in the first or second plasma electrolytic oxidation treatment comprises: sodium polyphosphate 10 g / L to 30 g / L, sodium silicate 10 g / L to 40 g / L, sodium aluminate 10 g / L to 30 g / L, sodium oxalate 5 g / L to 30 g / L, sodium hydroxide 2 g / L to 10 g / L, and disodium ethylenediaminetetraacetate 2 g / L to 10 g / L. In another embodiment, the bath temperature in the first or second plasma electrolytic oxidation treatment is controlled at 25°C to 50°C. Selecting appropriate electrolytes and bath temperatures allows for sufficient plasma electrolytic oxidation of the zirconium alloy cladding, thereby facilitating the formation of a high-quality oxide film.

[0039] The present invention is further illustrated below with specific embodiments:

[0040] Example 1

[0041] This embodiment provides a zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents. The zirconium alloy cladding includes a zirconium alloy substrate, on the surface of which a zirconium oxide base film layer and an alumina-zirconium mixed film layer are sequentially disposed. The thickness of the zirconium oxide base film layer is 3 μm; the thickness of the alumina-zirconium mixed film layer is 30 μm.

[0042] It is prepared by the following method:

[0043] A first plasma electrolytic oxidation treatment is performed on a zirconium alloy substrate to generate a zirconium oxide substrate layer in situ on the surface of the zirconium alloy substrate, thereby obtaining a first zirconium alloy treated part.

[0044] The first zirconium alloy part is subjected to a second plasma electrolytic oxidation treatment to generate an in-situ alumina-zirconium mixed film layer on the surface of the first zirconium alloy part, thus obtaining the finished product.

[0045] In the first plasma electrolytic oxidation treatment, an anodic unidirectional pulse treatment is used to generate a zirconium oxide substrate layer in situ on the surface of the zirconium alloy workpiece. The power supply parameters for the anodic unidirectional pulse treatment are: forward voltage of 200V, duty cycle of 45%, pulse frequency of 800Hz, and treatment time of 10 minutes.

[0046] In the second plasma electrolytic oxidation treatment, a bidirectional pulse treatment with cathode and anode is used to generate an alumina-zirconium mixed film layer in situ on the surface of the first zirconium alloy treatment part. The power supply parameters of the bidirectional pulse treatment with cathode and anode are: positive voltage 250V, duty cycle 45%, pulse frequency 800Hz; negative voltage 60V, duty cycle 25%, pulse frequency 800Hz, and treatment time 10 minutes.

[0047] The electrolyte used in the first or second plasma electrolytic oxidation treatment includes: 25 g / L sodium polyphosphate, 25 g / L sodium silicate, 30 g / L sodium aluminate, 20 g / L sodium oxalate, 2 g / L sodium hydroxide, and 2 g / L disodium ethylenediaminetetraacetate; the bath temperature is controlled at 30°C.

[0048] Example 2

[0049] This embodiment provides a zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents. The zirconium alloy cladding includes a zirconium alloy substrate, on the surface of which a zirconium oxide base film layer and an alumina-zirconium mixed film layer are sequentially disposed. The thickness of the zirconium oxide base film layer is 2 μm; the thickness of the alumina-zirconium mixed film layer is 25 μm.

[0050] It is prepared by the following method:

[0051] A first plasma electrolytic oxidation treatment is performed on a zirconium alloy substrate to generate a zirconium oxide substrate layer in situ on the surface of the zirconium alloy substrate, thereby obtaining a first zirconium alloy treated part.

[0052] The first zirconium alloy part is subjected to a second plasma electrolytic oxidation treatment to generate an in-situ alumina-zirconium mixed film layer on the surface of the first zirconium alloy part, thus obtaining the finished product.

[0053] In the first plasma electrolytic oxidation treatment, an anodic unidirectional pulse treatment is used to generate a zirconium oxide substrate layer in situ on the surface of the zirconium alloy workpiece. The power supply parameters for the anodic unidirectional pulse treatment are: forward voltage of 200V, duty cycle of 45%, pulse frequency of 200Hz, and treatment time of 10 minutes.

[0054] In the second plasma electrolytic oxidation treatment, a bidirectional pulse treatment with cathode and anode is used to generate an alumina-zirconium mixed film layer in situ on the surface of the first zirconium alloy treatment part. The power supply parameters of the bidirectional pulse treatment with cathode and anode are: positive voltage 250V, duty cycle 45%, pulse frequency 200Hz; negative voltage 60V, duty cycle 25%, pulse frequency 200Hz, and treatment time 10 minutes.

[0055] The electrolyte used in the first or second plasma electrolytic oxidation treatment includes: 15 g / L sodium polyphosphate, 15 g / L sodium silicate, 30 g / L sodium aluminate, 20 g / L sodium oxalate, 5 g / L sodium hydroxide, and 2 g / L disodium ethylenediaminetetraacetate; the bath temperature is controlled at 30°C.

[0056] Example 3

[0057] This embodiment provides a zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents. The zirconium alloy cladding includes a zirconium alloy substrate, on the surface of which a zirconium oxide base film layer and an alumina-zirconium mixed film layer are sequentially disposed. The thickness of the zirconium oxide base film layer is 4 μm; the thickness of the alumina-zirconium mixed film layer is 20 μm.

[0058] It is prepared by the following method:

[0059] A first plasma electrolytic oxidation treatment is performed on a zirconium alloy substrate to generate a zirconium oxide substrate layer in situ on the surface of the zirconium alloy substrate, thereby obtaining a first zirconium alloy treated part.

[0060] The first zirconium alloy part is subjected to a second plasma electrolytic oxidation treatment to generate an in-situ alumina-zirconium mixed film layer on the surface of the first zirconium alloy part, thus obtaining the finished product.

[0061] In the first plasma electrolytic oxidation treatment, an anodic unidirectional pulse treatment is used to generate a zirconium oxide substrate layer in situ on the surface of the zirconium alloy workpiece. The power supply parameters for the anodic unidirectional pulse treatment are: forward voltage of 200V, duty cycle of 45%, pulse frequency of 800Hz, and treatment time of 10 minutes.

[0062] In the second plasma electrolytic oxidation treatment, a bidirectional pulse treatment with cathode and anode is used to generate an alumina-zirconium mixed film layer in situ on the surface of the first zirconium alloy treatment part. The power supply parameters of the bidirectional pulse treatment with cathode and anode are: positive voltage 250V, duty cycle 45%, pulse frequency 800Hz; negative voltage 60V, duty cycle 45%, pulse frequency 800Hz, and treatment time 10 minutes.

[0063] The electrolyte used in the first or second plasma electrolytic oxidation treatment includes: 15 g / L sodium polyphosphate, 15 g / L sodium silicate, 30 g / L sodium aluminate, 20 g / L sodium oxalate, 5 g / L sodium hydroxide, and 2 g / L disodium ethylenediaminetetraacetate; the bath temperature is controlled at 30°C.

[0064] Figure 1 The image shows a surface SEM image of the zirconium alloy cladding used for fault-tolerant fuel in nuclear power plant reactor accidents, obtained in Example 1. Figure 2 This is a cross-sectional SEM image of the first zirconium alloy treated part obtained in Example 1. Figure 3 This is a cross-sectional SEM image of the zirconium alloy cladding used for fault-tolerant fuel in nuclear power plant reactor accidents, obtained in Example 1. Figures 1-3 It is understood that the zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents provided by the present invention has excellent interfacial bonding between the zirconium alloy substrate and the zirconium oxide base film, as well as between the zirconium oxide base film and the alumina-zirconium mixed film, with uniform thickness and dense structure of each layer.

[0065] In summary, the zirconium alloy cladding for fault-tolerant fuel in nuclear power plant accidents provided by this invention includes a zirconium alloy substrate, on the surface of which a zirconium oxide base film layer and an alumina-zirconium mixed film layer are sequentially disposed. The interfacial bonding between the zirconium alloy substrate and the zirconium oxide base film layer, and between the zirconium oxide base film layer and the alumina-zirconium mixed film layer, is excellent. Each layer has uniform thickness and a dense structure, ultimately exhibiting good corrosion resistance, wear resistance, and resistance to high-temperature water vapor corrosion. Furthermore, the preparation method of the zirconium alloy cladding for fault-tolerant fuel in nuclear power plant accidents provided by this invention eliminates the need for a metal transition layer, directly generating an oxide ceramic layer in situ on the surface of the zirconium alloy substrate. This does not reduce the neutron absorption efficiency of the nuclear fuel and does not contaminate the nuclear fuel reaction system.

[0066] The above description is a preferred embodiment of the invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the invention, and these improvements and modifications are also considered to be within the scope of protection of the invention.

Claims

1. A zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents, characterized in that, The zirconium alloy cladding includes a zirconium alloy substrate, and a zirconium oxide base film layer and a mixed alumina-zirconium film layer are sequentially disposed on the surface of the zirconium alloy substrate. The method for preparing the zirconium alloy cladding includes the following steps: A first plasma electrolytic oxidation treatment is performed on a zirconium alloy substrate to generate a zirconium oxide substrate layer in situ on the surface of the zirconium alloy substrate, thereby obtaining a first zirconium alloy treated part. The first zirconium alloy part is subjected to a second plasma electrolytic oxidation treatment to generate an in-situ alumina-zirconium mixed film layer on the surface of the first zirconium alloy part, thereby obtaining the finished product; In the first plasma electrolytic oxidation treatment, unidirectional pulse treatment of the anode is used to generate a zirconium oxide substrate layer in situ on the surface of the zirconium alloy workpiece. The power supply parameters for the unidirectional pulse processing of the anode are: forward voltage of 200V~250V, duty cycle of 25%~45%, pulse frequency of 100Hz~1000Hz, and processing time of 5min~30min. In the second plasma electrolytic oxidation treatment, a bidirectional pulse treatment of cathode and anode is used to generate an alumina-zirconium mixed film layer in situ on the surface of the first zirconium alloy part. The power supply parameters for the bidirectional pulse processing of cathode and anode are as follows: positive voltage 200V~250V, duty cycle 30%~60%, pulse frequency 100Hz~1000Hz, negative voltage 50V~80V, duty cycle 20%~30%, pulse frequency 100Hz~1000Hz, and processing time 5min~30min.

2. The zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents as described in claim 1, characterized in that, The thickness of the zirconium oxide substrate is 2μm to 6μm.

3. The zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents as described in claim 1, characterized in that, The thickness of the alumina-zirconia hybrid film is 10 μm to 50 μm.

4. A method for preparing a zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents as described in any one of claims 1 to 3, characterized in that, The electrolyte used in the first or second plasma electrolytic oxidation treatment includes: sodium polyphosphate 10g / L~30g / L, sodium silicate 10g / L~40g / L, sodium aluminate 10g / L~30g / L, sodium oxalate 5g / L~30g / L, sodium hydroxide 2g / L~10g / L and disodium ethylenediaminetetraacetate 2g / L~10g / L.

5. The method for preparing zirconium alloy cladding for fault-tolerant fuel in nuclear power plant reactor accidents as described in claim 4, characterized in that, In the first plasma electrolytic oxidation treatment or the second plasma electrolytic oxidation treatment, the temperature of the bath solution is controlled at 25℃~50℃.

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