A preparation method and film forming device for heterogeneous tritium barrier coating on inner and outer walls of pipe fittings

Abstract

The present invention belongs to the helium cooling technology of fusion reactor, and specifically relates to a preparation method and film-forming device for heterogeneous tritium barrier coating on the inner and outer walls of pipe fittings. After electrolytic polishing, the static tube is placed on a three-way parallel pipeline. MOD liquid circulates through the liquid tank and the static tube, forming a uniform liquid film in the static tube. After cooling, the two ends of the static tube are sealed, baked, and then cooled. Sintering is repeated several times. The film-forming device has a liquid tank, and the two ends of the connecting pipeline are respectively installed with circulating pump A and circulating pump B. The three-way parallel pipeline between the two is installed with the above-mentioned static tube. It can not only be used for the preparation of coatings on the inner surface of complex cavities / pipelines, but also can prepare heterogeneous tritium barrier coatings on the inner and outer surfaces to meet the different functional requirements of the inner and outer walls of the same pipeline. The process operation is simple and can realize industrial large-scale production.

Description

Technical Field

[0001] The invention belongs to the helium cooling technology of fusion reactor, and specifically relates to a preparation method and a film forming device of a heterogeneous tritium barrier coating on the inner and outer walls of a pipe. Background Art

[0002] The research and development of high-performance tritium barrier coating (TPB) preparation technology for the inner wall of the complex breeding unit flow channel of the helium-cooled solid tritium breeder blanket (HCCB-TBM) of the deuterium-tritium (DT) fusion reactor is a difficult engineering problem faced by this field. It is the key to achieving tritium self-sustaining and tritium safety, and directly affects whether the fusion reactor can be applied in engineering. This is because tritium is radioactive, has strong permeability and diffusivity, and is in a complex environment such as high temperature, high heat load, and helium ion irradiation. It is very easy to cause tritium retention, hydrogen embrittlement, and tritium release to the environment in the tritium-related components in the area, leading to tritium loss, safety accidents, radioactive pollution, and increased economic costs; at the same time, the TBM is located in the annular vacuum chamber, right after the first wall facing the plasma, and the working conditions are also very harsh: the surface heat load is greater than 0.5MW / m 2 , 14.1MeV high energy neutron flux is greater than 1018n / m 2 ·s and complex corrosive environment. In such extreme environment, TBM structural materials face severe challenges in achieving precise combination of structural materials, coolant materials, tritium breeding materials, etc., and facing severe tritium permeability.

[0003] Under the condition of limited improvement of components and organizational structure, coating a certain thickness of tritium permeation barrier (TPB) on the surface of TBM structural materials can be regarded as the most effective and convenient technical means to reduce tritium penetration and protect the substrate. However, the complex breeding unit circuit brings great difficulties to the preparation of the inner wall tritium barrier coating. Especially compared with the traditional HCCB-TBM, whether the more flexible and precise three-layer casing structure of the new breeding unit design can be realized in engineering application depends on the breakthrough and innovation of the inner wall tritium barrier coating technology to realize the preparation of special coatings for different functional areas of the inner and outer walls of the same pipeline. As the development of DT nuclear fusion reactors has entered the engineering feasibility stage from the basic research stage, it is urgent to develop potential TPB coatings and inner and outer wall coating preparation technologies.

[0004] In 2010, the National Institute of Fusion Science of Japan proposed the metal organic decomposition (MOD) technology to prepare tritium barrier coatings. The coating preparation research can be carried out on the inner wall of complex cavities, which has aroused strong interest in the scientific and engineering communities in recent years. Compared with the traditional Sol-Gel method, the MOD precursor is an organic compound formed by the direct combination of metal atoms with C atoms and then with an organic compound. It is very stable in the atmosphere and insensitive to water and carbon dioxide. This feature of the MOD precursor makes the MOD coating process extremely simple. Compared with the traditional Sol-Gel method, the MOD method has shown good application potential and novel technical advantages. Since the MOD-TPB coating technology was proposed, the National Institute of Fusion Science of Japan, the University of Tokyo and many fusion research institutions in Europe and the United States have carried out a series of relatively systematic research. However, my country's research on the use of MOD technology to prepare TPB coatings is currently in its infancy and urgently needs to be studied. . Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a heterogeneous tritium barrier coating on the inner and outer walls of a pipe and a film-forming device, which is suitable for the inner and outer surfaces of the pipe, has a simple preparation process and excellent performance.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing a heterogeneous tritium barrier coating on the inner and outer walls of a pipe, comprising the following steps:

[0008] 1) Electrolytically polish the three stationary tubes, rinse them with deionized water, and blow dry them for later use;

[0009] 2) Three static tubes are placed on a three-way parallel pipeline, and the two ends of the parallel pipeline are connected to the outlet and inlet of the liquid tank respectively; the MOD liquid circulates through the liquid tank and the static tube, forming a uniform liquid film in the static tube;

[0010] 3) baking the stationary tube coated with the wet gel and cooling it to room temperature;

[0011] 4) Seal both ends of the stationary tube and evenly coat the outer wall of the stationary tube with commercial Al-03-P or Cr-03 MOD liquid;

[0012] 5) The tube is suspended in air for 1 to 5 minutes, then baked and cooled to room temperature;

[0013] 6) Repeat the above steps 5) to 6) 10 to 50 times;

[0014] 7) Sample sintering

[0015] The stationary tube is placed at a temperature of 700°C to 1000°C for 1 to 2 hours for sintering.

[0016] The three stationary pipes are respectively a CLF-1 steel pipe, a 316L internally polished round pipe and a U-shaped pipe.

[0017] In the step 2), the circulating flow rate of the MOD liquid is 0.3-2 m / s, a switch is installed on the pipeline, and the MOD liquid is left to stand for 300-600 seconds after the circulation is stopped, and then discharged.

[0018] In the step 2), the stationary tube is suspended in the air for 1 to 5 minutes.

[0019] The pulling speed during the coating process in step 4) is 10-40 cm / min, and the immersion time is 300-600 s.

[0020] The MOD liquid in step 2) is commercial Cr-03 or Al-03-P.

[0021] In the step 7), the heating rate is 2-5°C / min, and the temperature is naturally cooled along with the furnace during cooling.

[0022] A liquid phase flow film forming device comprises a liquid tank, wherein the outlet and inlet ends of the liquid tank are respectively connected to pipelines, namely, an outlet pipeline and an inlet pipeline, a circulation pump A and a circulation pump B are respectively installed on the outlet pipeline and the inlet pipeline, and three pipelines are connected in parallel between the circulation pump A and the circulation pump B;

[0023] On one of the pipelines, a circulation pump C and a stationary pipe A are installed in sequence according to the direction of liquid flow;

[0024] On the second pipeline, a circulation pump D and a stationary pipe B are installed in sequence according to the direction of liquid flow;

[0025] On the third pipeline, a circulation pump E and a static pipe C are installed in sequence according to the direction of liquid flow.

[0026] A pipeline switch is provided between the circulating pump and the static pipe.

[0027] The stationary tube A6, stationary tube B and stationary tube C are CLF-1, 316L inner polished round tube and U-shaped tube respectively.

[0028] The remarkable effects of the present invention are as follows:

[0029] (1) Compared with traditional coating preparation technologies such as physical sputtering deposition, metal organic chemical vapor deposition, electrochemical deposition, hot dip plating and the like, the present invention can not only be used to prepare coatings on the inner surface of complex cavities / pipelines, but can also prepare heterogeneous tritium barrier coatings on the inner and outer surfaces to meet different functional requirements for the inner and outer walls of the same pipeline. The process operation is simple and can be used for industrial large-scale production.

[0030] (2) The present invention can replace the MOD precursor arbitrarily to prepare different types of heterogeneous coatings on the inner and outer walls of the tube; the coating structure, uniformity, deposition rate, thickness, etc. can be controlled by adjusting the process parameters such as the circulation flow rate, standing time, pulling speed and immersion time, baking and annealing temperature, and number of cycles, and the controllability is strong;

[0031] (3) The homemade liquid flow film forming device is simple and easy to maintain and can also be operated in a vacuum glove box, which can realize the preparation and development of high-quality tritium barrier coatings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of a liquid phase flow film forming device;

[0033] Figure 2 Schematic diagram of the inner and outer wall Al2O3 / substrate / Al2O3 tritium barrier coating prepared in Example 1;

[0034] Figure 3 This is a structural diagram of the inner and outer wall Cr2O3 / substrate / Al2O3 tritium barrier coating prepared in Example 2;

[0035] Figure 4 This is a structural diagram of the inner and outer wall Al2O3 / substrate / Cr2O3 tritium barrier coating prepared in Example 3;

[0036] In the figure: 1. Liquid tank; 2. Circulation pump A; 3. Circulation pump C; 4. Circulation pump D; 5. Circulation pump E; 6. Still pipe A; 7. Still pipe B; 8. Still pipe C; 9. Circulation pump B; 10. Outlet pipeline; 11. Inlet pipeline; 12. Pipeline switch. DETAILED DESCRIPTION

[0037] The present invention will be further described below through the accompanying drawings and specific implementation methods.

[0038] like Figure 1 The liquid phase flow film forming device shown includes a liquid tank 1, the outlet and inlet ends of the liquid tank 1 are connected to pipelines, namely, the outlet pipeline 10 and the inlet pipeline 11, and the outlet pipeline 10 and the inlet pipeline 11 are respectively installed with a circulation pump A2 and a circulation pump B9.

[0039] Connect three pipelines in parallel between circulating pump A2 and circulating pump B9;

[0040] On one of the pipelines, a circulation pump C3 and a static pipe A 6 are installed in sequence according to the direction of liquid flow;

[0041] On the second pipeline, a circulation pump D4 and a static pipe B7 are installed in sequence according to the direction of liquid flow;

[0042] On the third pipeline, a circulation pump E5 and a static pipe C8 are installed in sequence according to the direction of liquid flow;

[0043] Among them, the stationary tube A6 is a low-activated ferrite martensite CLF-1 steel tube, the stationary tube B7 is a 316L internally polished round tube, and the stationary tube C8 is a U-shaped tube, which respectively represent the types of structural materials that may be used in the future helium-cooled blanket.

[0044] Pipeline switches are installed between the circulation pump and the static pipe, wherein the pipeline switch 12 between 8 and 9 is an outlet switch for controlling the liquid to stagnate in the static pipe to implement coating on the inner wall of the static pipe.

[0045] When in use, the inner wall coating is prepared by the above-mentioned liquid phase flow film forming device at room temperature. Place an appropriate amount of commercial Al-03-PMOD liquid in 1 (liquid placement tank), with the liquid level higher than the inlet and outlet pipeline positions, open the circulation switch in the pipeline, and use the circulation pump to circulate the MOD liquid on the inner wall of the tube at a flow rate of 0.5s. After 3 minutes, close the pipeline switch to stop the circulation, and let the MOD liquid stand on the inner wall of the tube (6, 7, 8) for 300 to 600s, and then open the outlet switch 12 to discharge the MOD liquid, and suspend the sample in the air for 3 minutes to form a uniform liquid film on the inner wall of the tube;

[0046] The method steps are as follows.

[0047] (1) The processed CLF-1, 316L internally polished round tube, and U-shaped tube (i.e., stationary tube A6, stationary tube B7, and stationary tube C8) are electrolytically polished, degreased, and rusted until the mirror surface is smooth, then rinsed with deionized water and blown dry for use;

[0048] (2) Using the above-mentioned liquid phase flow film forming device at room temperature, commercial Cr-03 or Al-03-P MOD liquid is circulated on the inner wall of the tube at a flow rate of 0.3 to 2 m / s. After 3 minutes, the circulation is stopped, and the MOD liquid is allowed to stand on the inner wall of the tube for 300 to 600 seconds. Then, the MOD liquid is discharged and the stationary tube is suspended in the air for 1 to 5 minutes to form a uniform liquid film on the inner wall of the tube.

[0049] (3) baking the stationary tube coated with the wet gel in (2) at 120° C. for 10 min in a gel baking machine and cooling naturally to room temperature;

[0050] (4) Repeat the above steps (2) to (4) 10 to 50 times;

[0051] (5) Seal both ends of the stationary tube obtained in (4), and evenly coat the outer wall of the tube with commercial Al-03-P or Cr-03 MOD liquid by conventional immersion and pulling method, with a pulling speed of 10 to 40 cm / min and an immersion time of 300 to 600 s;

[0052] (6) After the impregnation in step (5) is suspended in air for 1 to 5 minutes, baked in a glue baking machine at 120° C. for 10 minutes, and naturally cooled to room temperature;

[0053] (7) Repeat the above steps (5) to (6) 10 to 50 times;

[0054] (8) The stationary tube obtained in the above step (7) is placed in a high-temperature vacuum box-type sintering furnace and subjected to heat treatment at 700°C to 1000°C for 1 to 2 hours to obtain a Cr2O3 / substrate / Al2O3 or Al2O3 / substrate / Cr2O3 heterogeneous tritium barrier coating on the substrate. The heating rate of this step is 3°C / min, and the temperature is naturally cooled along with the furnace.

[0055] The following parameters are preferred:

[0056] In step 2), the MOD circulation flow rate is 0.5 m / s and the mixture is allowed to stand for 300 s;

[0057] In step (5), the pulling speed is 10 cm / min; the substrate is placed in the MOD solution for 300 s;

[0058] In steps (2) and (6), the sample is suspended in air for 3 minutes;

[0059] In step (3), the mixture is baked in a baking machine at 120° C. for 10 min;

[0060] In steps (4) and (7), steps (2) to (4) and (5) to (6) are preferably repeated 20 times each.

[0061] Embodiment 1:

[0062] (1) The processed CLF-1 internal polished round tube is electrolytically polished, degreased, and rust-removed until the surface is mirror-smooth, then rinsed with deionized water and blown dry for standby use, wherein the electrolytic polishing liquid is 10% perchloric acid, the degreasing agent formula is composed of 160g / L sodium carbonate, 45g / L sodium citrate, 5g / L activator, and 50g / L sodium phosphate, and the rust remover is 110g / L industrial hydrochloric acid;

[0063] (2) The inner wall coating was prepared using a homemade liquid flow film forming device at room temperature.

[0064] Place an appropriate amount of commercial Al-03-P MOD liquid in the liquid tank 1, with the liquid level higher than the inlet and outlet. Open the circulation switch in the pipeline, and use the circulation pump to circulate the MOD liquid on the inner wall of the tube at a flow rate of 0.5s. After 3 minutes, close the pipeline switch to stop the circulation, and let the MOD liquid stand on the inner wall of the stationary tube for 300-600s, then open the outlet switch to discharge the MOD liquid, and suspend the sample in the air for 3 minutes to form a uniform liquid film on the inner wall of the tube.

[0065] (3) baking the stationary tube coated with the wet gel in (2) at 120° C. for 10 min in a gel baking machine and cooling naturally to room temperature;

[0066] (4) Repeat the above steps (2) to (4) 20 times;

[0067] (5) Seal both ends of the stationary tube obtained in (4), and evenly coat the outer wall of the tube with commercial Al-03-P MOD liquid by conventional immersion and pulling method, with a pulling speed of 10 cm / min and an immersion time of 600 s;

[0068] (6) After the impregnation in step (5) above, the static tube is suspended in air for 3 minutes, baked in a glue baking machine at 120° C. for 10 minutes, and naturally cooled to room temperature;

[0069] (7) Repeat the above steps (5) to (6) 20 times;

[0070] (8) The stationary tube obtained in the above step (7) is placed in a high-temperature vacuum box-type sintering furnace and heat treated at 700°C for 1 hour. The heating rate of this step is 3°C / min. When cooling down, it is cooled naturally with the furnace to obtain an Al2O3 / substrate / Al2O3 homogeneous tritium barrier coating on the substrate. The structural schematic diagram is shown in Figure 2.

[0071] Embodiment 2:

[0072] (1) The processed 316L U tube is electrolytically polished, degreased, and rust-removed until the surface is mirror-smooth, then rinsed with deionized water and blown dry for use, wherein the electrolytic polishing liquid is 10% perchloric acid, the degreasing agent formula is composed of 160g / L sodium carbonate, 45g / L sodium citrate, 5g / L activator, and 50g / L sodium phosphate, and the rust remover is 110g / L industrial hydrochloric acid;

[0073] (2) The inner wall coating was prepared using a liquid flow film forming apparatus at room temperature.

[0074] Place an appropriate amount of commercial Cr-03 MOD liquid in the liquid tank 1, with the liquid level higher than the inlet and outlet. Open the circulation switch in the pipeline, and use the circulation pump to circulate the MOD liquid on the inner wall of the tube at a flow rate of 0.5s. After 3 minutes, close the pipeline switch to stop the circulation. Let the MOD liquid stand on the inner wall of the static tube for 300-600s, then open the outlet switch to discharge the MOD liquid, and suspend the static tube in the air for 3 minutes to form a uniform liquid film on the inner wall of the tube.

[0075] (3) baking the wet gel sample coated in (2) at 120° C. for 10 min in a baking machine and cooling naturally to room temperature;

[0076] (4) Repeat the above steps (2) to (4) 20 times;

[0077] (5) Seal both ends of the stationary tube obtained in (4), and evenly coat the outer wall of the tube with commercial Al-03-P MOD liquid by conventional immersion and pulling method, with a pulling speed of 10 cm / min and an immersion time of 600 s;

[0078] (6) After the sample impregnated in step (5) is suspended in air for 5 minutes, it is baked in a baking machine at 120° C. for 10 minutes, and naturally cooled to room temperature;

[0079] (7) Repeat the above steps (5) to (6) 20 times;

[0080] (8) The stationary tube obtained in the above step (7) is placed in a high-temperature vacuum box-type sintering furnace and heat treated at 700°C for 2 hours. The heating rate of this step is 3°C / min. When cooling down, it is cooled naturally with the furnace to obtain an Al2O3 / substrate / Cr2O3 heterogeneous tritium barrier coating on the substrate. The structural schematic diagram is shown in Figure 3.

[0081] Embodiment 3:

[0082] (1) The processed CLF-1 internal polished round tube is electrolytically polished, degreased, and rust-removed until the surface is mirror-smooth, then rinsed with deionized water and blown dry for standby use, wherein the electrolytic polishing liquid is 10% perchloric acid, the degreasing agent formula is composed of 160g / L sodium carbonate, 45g / L sodium citrate, 5g / L activator, and 50g / L sodium phosphate, and the rust remover is 110g / L industrial hydrochloric acid;

[0083] (2) Prepare the inner wall coating in a liquid phase flow film forming device at room temperature. Place an appropriate amount of commercial Cr-03 MOD liquid in 1 (liquid tank) with the liquid level higher than the inlet and outlet. Open the circulation switch in the pipeline and use the circulation pump to circulate the MOD liquid on the inner wall of the tube at a flow rate of 0.5s. After 3 minutes, close the pipeline switch to stop the circulation. Let the MOD liquid stand on the inner wall of the stationary tube for 300 to 600 seconds, then open the outlet switch to discharge the MOD liquid, and suspend the sample in the air for 3 minutes to form a uniform liquid film on the inner wall of the tube.

[0084] (3) baking the tube coated with the wet gel in (2) at 120° C. for 10 min in a gel baking machine and cooling naturally to room temperature;

[0085] (4) Repeat the above steps (2) to (4) 20 times;

[0086] (5) The sample in (4) was uniformly coated on the inner and outer walls of the tube using the conventional immersion and pulling method with commercial Al-03-P MOD liquid, the pulling speed was 10 cm / min, and the immersion time was 600 s;

[0087] (6) After the impregnation in step (5) is suspended in air for 5 minutes, the tube is baked in a baking machine at 120° C. for 10 minutes, and then cooled naturally to room temperature;

[0088] (7) Repeat the above steps (5) to (6) 20 times;

[0089] (8) The stationary tube obtained in the above step (7) is placed in a high-temperature vacuum box-type sintering furnace and subjected to heat treatment at 1000°C for 2 hours. The heating rate of this step is 3°C / min. The tube is cooled naturally along with the furnace during cooling. Thus, an Al2O3 / substrate / Cr2O3-Al2O3 heterogeneous tritium barrier coating is obtained on the substrate. The structural schematic diagram is shown in FIG4. The obtained inner wall coating is a composite tritium barrier coating with a double-layer structure and better hydrogen barrier performance.

Claims

1. A method for preparing a heterogeneous tritium barrier coating on the inner and outer walls of a pipe, characterized in that: The steps include: 1) Electrolytically polish the three stationary tubes, rinse them with deionized water, and blow dry them for later use; 2) Three static tubes are placed on a three-way parallel pipeline, and the two ends of the parallel pipeline are connected to the outlet and inlet of the liquid tank respectively; the MOD liquid circulates through the liquid tank and the static tube, forming a uniform liquid film in the static tube; 3) baking the stationary tube coated with the wet gel and cooling it to room temperature; 4) Seal both ends of the stationary tube and evenly coat the outer wall of the stationary tube with commercial Al-03-P or Cr-03 MOD liquid; 5) The tube is suspended in air for 1 to 5 minutes, then baked and cooled to room temperature; 6) Repeat the above steps 5) to 6) 10 to 50 times; 7) Sample sintering The stationary tube is placed at a temperature of 700°C to 1000°C for 1 to 2 hours for sintering.

2. The method for preparing a heterogeneous tritium barrier coating on the inner and outer walls of a pipe according to claim 1, characterized in that: The three stationary pipes are respectively a CLF-1 steel pipe, a 316L internally polished round pipe and a U-shaped pipe.

3. The method for preparing a heterogeneous tritium barrier coating on the inner and outer walls of a pipe according to claim 2, characterized in that: In the step 2), the circulating flow rate of the MOD liquid is 0.3-2 m / s, a switch is installed on the pipeline, and the MOD liquid is left to stand for 300-600 seconds after the circulation is stopped, and then discharged.

4. The method for preparing a heterogeneous tritium barrier coating on the inner and outer walls of a pipe as claimed in claim 3, characterized in that: In the step 2), the static tube is suspended in the air for 1 to 5 minutes.

5. The method for preparing a heterogeneous tritium barrier coating on the inner and outer walls of a pipe according to claim 1, characterized in that: The pulling speed during the coating process in step 4) is 10-40 cm / min, and the immersion time is 300-600 s.

6. The method for preparing a heterogeneous tritium barrier coating on the inner and outer walls of a pipe according to claim 1, characterized in that: The MOD liquid in step 2) is commercial Cr-03 or Al-03-P.

7. The method for preparing a heterogeneous tritium barrier coating on the inner and outer walls of a pipe according to claim 6, characterized in that: In the step 7), the heating rate is 2-5°C / min, and the temperature is naturally cooled along with the furnace during cooling.

8. A liquid phase flow film forming device, characterized in that: The invention comprises a liquid placing tank (1), wherein the outlet and the inlet of the liquid placing tank (1) are respectively connected to pipelines, namely an outlet pipeline (10) and an inlet pipeline (11), a circulation pump A (2) and a circulation pump B (9) are respectively installed on the outlet pipeline (10) and the inlet pipeline (11), and three pipelines are connected in parallel between the circulation pump A (2) and the circulation pump B (9); A circulation pump C (3) and a stationary pipe A (6) are installed in sequence on the first pipeline according to the direction of liquid flow; A circulation pump D (4) and a stationary pipe B (7) are installed on the second pipeline in sequence according to the direction of liquid flow; A circulation pump E (5) and a stationary pipe C (8) are installed on the third pipeline in sequence according to the direction of liquid flow; A pipeline switch is provided between the circulating pump and the static pipe.

9. A liquid phase flow film forming device as claimed in claim 8, characterized in that: The stationary tube A (6), stationary tube B (7) and stationary tube C (8) are CLF-1, 316L inner polished round tube and U-shaped tube respectively.

Images