Rod-shaped nuclear fuel element based on 3D printing and seal forming method thereof
Technical Field
The invention belongs to the technical field of nuclear power, and relates to a rod-shaped nuclear fuel element based on 3D printing and a seal forming method thereof.
Background
Nuclear fuel elements are the energy source of nuclear power plants and are also the core components of nuclear reactors. The fuel element is in the reactor under the environmental conditions of irradiation field, temperature field, velocity field and certain external pressure, and the working environment is very harsh. Structural materials such as fuel element cladding and end plugs are subjected to stress, strain, corrosion and the like caused by dimensional changes of core materials in addition to damage caused by irradiation.
Light water reactors are the primary reactor type of nuclear power plants, employing rod-like nuclear fuel elements. The active rod-shaped nuclear fuel element consists of short cylindrical fuel pellets, a cladding, an end plug, an air storage cavity compression spring and the like. The silicon carbide is an important functional structure ceramic material at present, has a series of excellent performances such as high temperature resistance, oxidation resistance, wear resistance and corrosion resistance, has the density of 1/4-1/3 of nickel-based high-temperature alloy, and is an important material for cladding of future nuclear fuel elements. After the accident of fukushima, a higher demand is made on the safety of nuclear fuel elements.
The rod-shaped nuclear fuel element in the prior art has a serious influence on the safety performance of the rod-shaped nuclear fuel element due to poor sealing performance of the cladding and the end plug, so how to ensure the sealing performance of the cladding and the end plug and further reduce the operating temperature of a fuel core body and the energy storage of a reactor core has important significance for improving the safety of the rod-shaped nuclear fuel element.
In view of the excellent water corrosion resistance and heat strength of SiC, the method has important application prospect in exploring the manufacture of silicon carbide ceramic matrix composite material parts in the energy field.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a rod-shaped nuclear fuel element based on 3D printing and a sealing forming method thereof, which solve the safety problem of the prior rod-shaped nuclear fuel element caused by poor sealing performance of a cladding and an end plug. The SiC is used as a cladding material of the rod-shaped fuel element, and a sealing ring is formed between the cladding and the end plug by 3D printing forming and laser cladding technology, so that the sealing problem between the cladding and the end plug is solved, and the safety of the rod-shaped nuclear fuel element is improved.
In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:
compared with the prior art, the invention has the following beneficial effects:
the invention discloses a rod-shaped nuclear fuel element, wherein a core body adopts a U with a hole in the middle3Si2Core body for increasing uranium loading capacity of fuel element3Si2A metallurgical bonding layer is arranged between the core body and the SiC cladding, so that U is eliminated3Si2Gap between core and cladding, U3Si2The mesopores in the center of the core can store fission gases and sufficiently absorb radiation swelling. The cladding is made of SiC ceramic material, SiC has the performances of high temperature resistance, oxidation resistance, abrasion resistance, corrosion resistance, thermal shock resistance and the like, meanwhile, a SiC sealing ring is arranged between the end plug and the SiC cladding, the SiC sealing ring and the SiC cladding form good matching, the sealing performance between the cladding and the end plug can be ensured, the operating temperature of the core body and the energy storage of the reactor core are reduced, and therefore the safety of the rod-shaped nuclear fuel element is improved.
The invention also discloses a nuclear fuel element sealing forming method based on 3D printing, which is characterized in that SiC is used as a cladding material of the fuel element, a printing ink prepared by mixing carbon fiber powder and photosensitive resin is used for printing a carbon fiber-based cladding sealing ring blank based on the 3D printing method, the carbon fiber-based cladding sealing ring blank is dried and pyrolyzed to prepare a carbon fiber preform substrate, and then Si powder is used for carrying out laser cladding on the carbon fiber-based cladding sealing ring blank, so that the SiC sealing ring is rapidly formed. A sealing ring is formed between the cladding and the end plug by using a 3D printing technology, so that the sealing problem between the cladding and the end plug is solved. The method omits the difficulties of assembly and processing and the like, can realize the preparation of the sealing ring with variable structure and variable thickness, has good sealing effect, can form good matching with the cladding material, has reasonable design and simple and convenient operation, can effectively improve the sealing performance of the rod-shaped nuclear fuel element, and is suitable for practical production.
Furthermore, the motion track of the rod-shaped nuclear fuel element rotates by taking the middle hole as an axis, the scanning path is that the rod-shaped nuclear fuel element rotates while the 3D printer nozzle is kept still, and the motion track of the rod-shaped nuclear fuel element is matched with the scanning path, so that the accuracy of a three-dimensional CAD model is further ensured, and the sealing effect of the rod-shaped nuclear fuel element is ensured.
Drawings
FIG. 1 is a schematic structural view of a rod-shaped nuclear fuel element according to the present invention;
wherein: 1-an end plug; 2-SiC sealing ring; 3-SiC cladding; 4-a metallurgical bonding layer; 5-U3Si2A core body; 6-mesopores.
Detailed Description
Referring to fig. 1, a rod-shaped nuclear fuel element, a SiC cladding 3 is installed between two end plugs 1, and a SiC sealing ring 2 is generated by a reaction between the end plugs 1 and the SiC cladding 3 through a 3D printing technology and a laser cladding technology. The SiC cladding 3 is internally provided with a U3Si2Core 5, and U3Si2The core 5 is located between two end plugs 1, U3Si2The core body 5 is internally provided with a middle hole 6, U3Si2A metallurgical bonding layer 4 is formed between the core 5 and the SiC clad shell 3 by a hot extrusion technique.
Example 1
A 3D printing seal forming method of a rod-shaped nuclear fuel element, comprising the steps of:
1) mixing short carbon fibers with the particle sizes of 100 micrometers, 40 micrometers, 20 micrometers and 5 micrometers according to the mass ratio of 2:4:1.5:2.5, wherein the length of the short carbon fibers is 5-10 micrometers to obtain fiber powder for 3D printing, and mixing the prepared carbon fiber powder and a photosensitive resin adhesive according to the mass ratio of 1:3 to obtain 3D printing ink;
2) establishing a three-dimensional CAD model of the cladding sealing ring, establishing a motion track of the rod-shaped nuclear fuel element, and matching the motion track with a scanning path, wherein the motion track of the rod-shaped nuclear fuel element rotates by taking the central hole 6 as a shaft, the scanning path rotates around the rod-shaped nuclear fuel element, and a nozzle of the 3D printer keeps still.
3) Importing the manufacturing data of the cladding sealing ring into a 3D printer, and printing and forming by using the printing ink prepared in the step 1) to obtain a biscuit of the carbon fiber-based cladding sealing ring;
4) and (2) carrying out vacuum drying and pyrolysis treatment on the biscuit of the carbon fiber-based encapsidation sealing ring, placing the biscuit in a vacuum degreasing furnace, carrying out vacuum drying for 4h at the temperature of 30 ℃, then heating to 300 ℃ at the heating rate of 1 ℃/min and preserving heat for 30min, then heating to 900 ℃ at the heating rate of 1 ℃/min and preserving heat for 3h, and obtaining the ring-mounted carbon fiber preform substrate.
5) Drying spherical high-purity Si powder with the granularity of 10 mu m, and carrying out laser cladding on the carbon fiber preform substrate in the atmosphere of argon protective gas, wherein the laser power is 350W, the scanning speed is 350mm/min, the powder feeding amount is 2.0g/min, and the temperature is 1400 ℃. The rod-shaped nuclear fuel element is rotated by taking the central hole 6 as an axis, the rod-shaped nuclear fuel element is formed in a mode that a laser processing head and a Si powder spray head are kept still, a carbon fiber preform and Si powder directly react under the action of laser to generate a SiC sealing ring 2, the SiC sealing ring 2 is positioned between the end plug 1 and the SiC cladding 3, the end plug 1 and the SiC cladding 3 are sealed, and then the completely sealed rod-shaped nuclear fuel element is obtained.
Example 2
A 3D printing seal forming method of a rod-shaped nuclear fuel element, comprising the steps of:
1) mixing short carbon fibers with the particle sizes of 100 micrometers, 40 micrometers, 20 micrometers and 5 micrometers according to the mass ratio of 2:4:1.5:2.5, wherein the length of the short carbon fibers is 5-10 micrometers to obtain fiber powder for 3D printing, and mixing the prepared carbon fiber powder and a photosensitive resin adhesive according to the mass ratio of 1:2.5 to obtain 3D printing ink;
2) establishing a three-dimensional CAD model of the cladding sealing ring, establishing a motion track of the rod-shaped nuclear fuel element, and matching the motion track with a scanning path, wherein the motion track of the rod-shaped nuclear fuel element rotates by taking the central hole 6 as a shaft, the scanning path rotates around the rod-shaped nuclear fuel element, and a nozzle of the 3D printer keeps still.
3) Importing the manufacturing data of the cladding sealing ring into a 3D printer, and printing and forming by using the printing ink prepared in the step 1) to obtain a biscuit of the carbon fiber-based cladding sealing ring;
4) and (2) carrying out vacuum drying and pyrolysis treatment on the biscuit of the carbon fiber-based encapsidation sealing ring, placing the biscuit in a vacuum degreasing furnace, carrying out vacuum drying for 3h at the temperature of 30 ℃, then heating to 300 ℃ at the heating rate of 1 ℃/min and preserving heat for 60min, then heating to 900 ℃ at the heating rate of 1 ℃/min and preserving heat for 5h, and obtaining the ring-mounted carbon fiber preform substrate.
5) Drying spherical high-purity Si powder with the granularity of 30 mu m, and carrying out laser cladding on the carbon fiber preform substrate in the atmosphere of argon protective gas, wherein the laser power is 450W, the scanning speed is 450mm/min, the powder feeding amount selection interval is 2.6g/min, and the temperature is 1400 ℃.
The rod-shaped nuclear fuel element is rotated by taking the central hole 6 as an axis, the rod-shaped nuclear fuel element is formed in a mode that a laser processing head and a Si powder spray head are kept still, a carbon fiber preform and Si powder directly react under the action of laser to generate a SiC sealing ring 2, the SiC sealing ring 2 is positioned between the end plug 1 and the SiC cladding 3, the end plug 1 and the SiC cladding 3 are sealed, and then the completely sealed rod-shaped nuclear fuel element is obtained.
Example 3
A 3D printing seal forming method of a rod-shaped nuclear fuel element, comprising the steps of:
1) mixing short carbon fibers with the particle sizes of 100 micrometers, 40 micrometers, 20 micrometers and 5 micrometers according to the mass ratio of 2:4:1.5:2.5, wherein the length of the short carbon fibers is 5-10 micrometers to obtain fiber powder for 3D printing, and mixing the prepared carbon fiber powder and a photosensitive resin adhesive according to the mass ratio of 1:4 to obtain 3D printing ink;
2) establishing a three-dimensional CAD model of the cladding sealing ring, establishing a motion track of the rod-shaped nuclear fuel element, and matching the motion track with a scanning path, wherein the motion track of the rod-shaped nuclear fuel element rotates by taking the central hole 6 as a shaft, the scanning path rotates around the rod-shaped nuclear fuel element, and a nozzle of the 3D printer keeps still.
3) Importing the manufacturing data of the cladding sealing ring into a 3D printer, and printing and forming by using the printing ink prepared in the step 1) to obtain a biscuit of the carbon fiber-based cladding sealing ring;
4) and (2) carrying out vacuum drying and pyrolysis treatment on the biscuit of the carbon fiber-based jacketing sealing ring, placing the biscuit in a vacuum degreasing furnace, carrying out vacuum drying for 4h at the temperature of 20 ℃, then heating to 350 ℃ at the heating rate of 1 ℃/min and preserving heat for 45min, then heating to 920 ℃ at the heating rate of 1 ℃/min and preserving heat for 6h to obtain the ring-mounted carbon fiber preform substrate.
5) Drying spherical high-purity Si powder with the granularity of 50 mu m, and carrying out laser cladding on the carbon fiber preform substrate in the atmosphere of argon protective gas, wherein the laser power is 300W, the scanning speed is 300mm/min, the powder feeding amount is 1.2g/min, and the temperature is 1500 ℃.
The rod-shaped nuclear fuel element is rotated by taking the central hole 6 as an axis, the rod-shaped nuclear fuel element is formed in a mode that a laser processing head and a Si powder spray head are kept still, a carbon fiber preform and Si powder directly react under the action of laser to generate a SiC sealing ring 2, the SiC sealing ring 2 is positioned between the end plug 1 and the SiC cladding 3, the end plug 1 and the SiC cladding 3 are sealed, and then the completely sealed rod-shaped nuclear fuel element is obtained.
Example 4
A 3D printing seal forming method of a rod-shaped nuclear fuel element, comprising the steps of:
1) mixing short carbon fibers with the particle sizes of 100 micrometers, 40 micrometers, 20 micrometers and 5 micrometers according to the mass ratio of 2:4:1.5:2.5, wherein the length of the short carbon fibers is 5-10 micrometers to obtain fiber powder for 3D printing, and mixing the prepared carbon fiber powder and a photosensitive resin adhesive according to the mass ratio of 1:2 to obtain 3D printing ink;
2) establishing a three-dimensional CAD model of the cladding sealing ring, establishing a motion track of the rod-shaped nuclear fuel element, and matching the motion track with a scanning path, wherein the motion track of the rod-shaped nuclear fuel element rotates by taking the central hole 6 as a shaft, the scanning path rotates around the rod-shaped nuclear fuel element, and a nozzle of the 3D printer keeps still.
3) Importing the manufacturing data of the cladding sealing ring into a 3D printer, and printing and forming by using the printing ink prepared in the step 1) to obtain a biscuit of the carbon fiber-based cladding sealing ring;
4) and (2) carrying out vacuum drying and pyrolysis treatment on the biscuit of the carbon fiber-based jacketing sealing ring, placing the biscuit in a vacuum degreasing furnace, carrying out vacuum drying for 4h at the temperature of 30 ℃, then heating to 400 ℃ at the heating rate of 1 ℃/min and preserving heat for 50min, then heating to 1000 ℃ at the heating rate of 1 ℃/min and preserving heat for 4h to obtain the ring-mounted carbon fiber preform substrate.
5) Drying spherical high-purity Si powder with the particle size of 100 mu m, and carrying out laser cladding on the carbon fiber preform substrate in the atmosphere of argon protective gas, wherein the laser power is 500W, the scanning speed is 500mm/min, the powder feeding amount is 3.2g/min, and the temperature is 1800 ℃.
The rod-shaped nuclear fuel element is rotated by taking the central hole 6 as an axis, the rod-shaped nuclear fuel element is formed in a mode that a laser processing head and a Si powder spray head are kept still, a carbon fiber preform and Si powder directly react under the action of laser to generate a SiC sealing ring 2, the SiC sealing ring 2 is positioned between the end plug 1 and the SiC cladding 3, the end plug 1 and the SiC cladding 3 are sealed, and then the completely sealed rod-shaped nuclear fuel element is obtained.
Example 5
A 3D printing seal forming method of a rod-shaped nuclear fuel element, comprising the steps of:
1) mixing short carbon fibers with the particle sizes of 100 micrometers, 40 micrometers, 20 micrometers and 5 micrometers according to the mass ratio of 2:4:1.5:2.5, wherein the length of the short carbon fibers is 5-10 micrometers to obtain fiber powder for 3D printing, and mixing the prepared carbon fiber powder and a photosensitive resin adhesive according to the mass ratio of 1:3 to obtain 3D printing ink;
2) establishing a three-dimensional CAD model of the cladding sealing ring, establishing a motion track of the rod-shaped nuclear fuel element, and matching the motion track with a scanning path, wherein the motion track of the rod-shaped nuclear fuel element rotates by taking the central hole 6 as a shaft, the scanning path rotates around the rod-shaped nuclear fuel element, and a nozzle of the 3D printer keeps still.
3) Importing the manufacturing data of the cladding sealing ring into a 3D printer, and printing and forming by using the printing ink prepared in the step 1) to obtain a biscuit of the carbon fiber-based cladding sealing ring;
4) and (2) carrying out vacuum drying and pyrolysis treatment on the biscuit of the carbon fiber-based jacketing sealing ring, placing the biscuit in a vacuum degreasing furnace, carrying out vacuum drying for 4h at the temperature of 25 ℃, then heating to 300 ℃ at the heating rate of 1 ℃/min and preserving heat for 40min, then heating to 950 ℃ at the heating rate of 1 ℃/min and preserving heat for 6h, and thus obtaining the ring-mounted carbon fiber preform substrate.
5) Drying spherical high-purity Si powder with the granularity of 65 mu m, and carrying out laser cladding on the carbon fiber preform substrate in the atmosphere of argon protective gas, wherein the laser power is 400W, the scanning speed is 400mm/min, the powder feeding amount is 2.5g/min, and the temperature is 1600 ℃.
The rod-shaped nuclear fuel element is rotated by taking the central hole 6 as an axis, the rod-shaped nuclear fuel element is formed in a mode that a laser processing head and a Si powder spray head are kept still, a carbon fiber preform and Si powder directly react under the action of laser to generate a SiC sealing ring 2, the SiC sealing ring 2 is positioned between the end plug 1 and the SiC cladding 3, the end plug 1 and the SiC cladding 3 are sealed, and then the completely sealed rod-shaped nuclear fuel element is obtained.
The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.