Boronizing treatment system for first wall surface of fusion device

Abstract

The invention discloses a boronizing treatment system for a first wall surface of a fusion device. The device comprises a special gas safety cabinet, a gas transmission pipeline, a gas shunting box, a safety interlocking system, a vacuum pumping unit and a tail gas processor, the special gas safety cabinet is connected with the gas shunting box through a gas transmission pipeline; the gas shunting box is connected with the vacuum chamber of the EAST fusion device through a gas transmission pipeline; the safety interlocking system is used for detecting the running states of the special gas safety cabinet, the gas shunting box, the gas monitor, the vacuum pumping unit and the tail gas processor; the vacuum pumping unit is connected with the EAST fusion device; and the tail gas treater is connected with an exhaust port of the mechanical dry pump of the vacuum pumping unit. The invention provides a simple, economical and effective boronizing system for treating the surface of the first wall in a fusion device, deuterated diborane is used as a working material, pollution caused by C and H impurities in a B2D6 sample in a boronizing experiment can be avoided, and the safety of a future experiment is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of boronization processing device, in particular to a boronization processing system for the surface of the first wall of a fusion device. BACKGROUND

[0002] In a magnetic confinement tokamak device, boronization coating film wall processing is widely used in the first wall processing before plasma discharge because of its strong adsorption capacity for oxygen impurities in the residual gas composition in the vacuum chamber. A layer of boron film is coated on the first wall of the vacuum chamber by chemical vapor deposition or plasma assisted method, thereby modifying the vacuum chamber wall to provide good first wall conditions for plasma discharge, thereby reducing impurities from the wall.

[0003] The boronization wall processing in the domestic fully superconducting tokamak EAST device currently uses carbon borane (C2B 10 H 12 ), which effectively suppresses the recycling level, impurity content and total radiation power in plasma discharge. However, since the carbon borane used in boronization wall processing contains hydrogen and carbon, it introduces additional hydrogen and carbon impurities, which ultimately leads to a higher hydrogen-deuterium ratio and an increase in tungsten impurity sputtering yield during plasma discharge. Experiments have found that after using carbon borane for boronization wall processing, the plasma density and Dα line radiation level are significantly higher than before boronization, and the hydrogen-deuterium ratio is increased, which is caused by the large amount of hydrogen contained in the working gas. During plasma discharge, through isotope exchange, a large amount of hydrogen is released into the plasma, thereby causing a high hydrogen particle recycling after boronization wall processing, and the hydrogen-deuterium ratio is difficult to reduce to within 25%, which cannot provide the best hydrogen-deuterium ratio conditions for the minority particle heating ion cyclotron heating system.

[0004] Therefore, it is urgent to develop a boronization wall processing system that does not contain carbon and hydrogen impurities for the surface boronization wall processing of the fully metal first wall of EAST and future fusion devices. Deuterated diborane only contains boron and deuterium elements, and is an ideal boronization wall processing material, but since it is a toxic and flammable gas, a safe and reliable system needs to be developed for the supply, monitoring and processing of deuterated diborane gas. SUMMARY

[0005] To solve the above technical problems, the purpose of the present application is to provide a boronization processing system for the surface of the first wall of a fusion device, to reduce the introduction of C and H impurities, to use deuterated diborane (B2D6) as the working material, and to design a new boronization wall processing system, which provides good boron film wall conditions for plasma discharge, and is of great significance for improving plasma performance.

[0006] To achieve the above purpose, the present application adopts the following technical solutions:

[0007] A boronization treatment system for a first wall surface of a fusion device, comprising a special gas safety cabinet, a gas transmission pipeline, a gas distribution box, a safety interlocking system, a vacuum air extractor set and a tail gas processor; the special gas safety cabinet is connected with the gas distribution box through the gas transmission pipeline; the gas distribution box is connected with a vacuum chamber of an EAST fusion device through the gas transmission pipeline; the safety interlocking system is used for detecting the running states of the special gas safety cabinet, the gas distribution box, the vacuum air extractor set and the tail gas processor; the vacuum air extractor set is connected with the EAST fusion device; and the tail gas processor is connected with an exhaust port of a mechanical dry pump of the vacuum air extractor set.

[0008] The special gas safety cabinet is used for supplying a deuterated diborane gas source and storing special gas to the EAST fusion device, and the special gas safety cabinet is a double-bottle full-automatic gas cylinder cabinet, and the whole special gas safety cabinet is in a negative pressure state.

[0009] The gas transmission pipeline is used for transporting the deuterated diborane gas, the gas transmission pipeline adopts a full-metal double-layer containing stainless steel pipeline, and the interlayer position of the double-layer pipeline is vacuumized to be within 0.01 MPa; and the connection position of the gas transmission pipeline is sealed in an automatic welding mode.

[0010] The inner tube size of the gas transmission pipeline is 1 / 4 inch, and the outer tube size is 1 / 2 inch.

[0011] The gas distribution box is located near the EAST fusion device, the inside of the gas distribution box is provided with one gas path inlet and three gas path outlets, and the gas distribution box is used for supplying and flow control of the deuterated diborane gas to three positions of the EAST fusion device respectively after the deuterated diborane gas is introduced from the special gas safety cabinet.

[0012] The boronization treatment system for the first wall surface of the fusion device further comprises a gas monitor, the gas monitor is used for detecting the concentration of the special gas, and the gas monitor is arranged at the inside and outside of the special gas safety cabinet, the inside and outside of the gas distribution box, the inlet of the EAST fusion device, the vacuum air extractor set and the tail gas processor.

[0013] The detection mode of the gas monitor is a pump suction type, and the alarm setting value of the gas monitor is B2D6>0.1 ppm and D2>1000 ppm.

[0014] The vacuum air extractor set is used for maintaining the deuterated diborane concentration during boronization and removing the deuterated diborane after the boronization is completed, and the vacuum air extractor set comprises a magnetic suspension molecular pump and a mechanical dry pump.

[0015] The pumping speed of the magnetic levitation molecular pump is 500~800 L / s, and the pumping speed of the mechanical dry pump is 15~25 L / s.

[0016] The exhaust gas processor is a dry adsorption type, and its maximum deuterated borane processing capacity is 3 L / min.

[0017] The beneficial effects of this invention are as follows:

[0018] This invention provides a simple, economical, and effective solution for the boronizing system of the first wall surface treatment in fusion devices. Using deuterated borane as the working material, it can avoid contamination from C and H impurities in B2D6 samples during boronizing experiments and ensure the safety of future experiments. More importantly, it provides a boronizing wall treatment system for fusion devices using a new type of pure working material. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a boronizing treatment system for the first wall surface of a fusion device according to the present invention.

[0020] The attached diagram is labeled as follows: 1-Special gas safety cabinet; 2-Gas transmission pipeline; 3a-First vacuum shut-off valve; 3b-Second vacuum shut-off valve; 3c-Third vacuum shut-off valve; 3d-Fourth vacuum shut-off valve; 3e-Fifth vacuum shut-off valve; 3f-Sixth vacuum shut-off valve; 4-Gas distribution box; 5-Gas monitor; 6-Magnetic levitation molecular pump; 7-Mechanical dry pump; 8-Exhaust gas processor. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] like Figure 1 As shown, a boronizing treatment system for the first wall surface of a fusion device includes a special gas safety cabinet 1, a gas transmission pipeline 2, a gas distribution box 4, a gas monitor 5, a safety interlock system, a vacuum pumping unit, and an exhaust gas processor 8.

[0023] One end of the special gas safety cabinet 1 is connected to the gas distribution box 4 via a gas transmission pipe 2, and the other end of the special gas safety cabinet 1 is connected to the exhaust gas processor 8. The two ends of the gas distribution box 4 are connected to the special gas safety cabinet 1 and the EAST fusion device respectively via gas transmission pipes 2. The gas monitors 5 are distributed inside and outside the special gas safety cabinet 1, inside and outside the gas distribution box 4, near the inlet of the EAST fusion device, the vacuum pump unit, and the exhaust gas processor 8. The front end of the vacuum pump unit is connected to the EAST fusion device, and the rear end of the vacuum pump unit is connected to the exhaust gas processor 8. The front end of the exhaust gas processor 8 is connected to the special gas safety cabinet 1 and the mechanical dry pump 7, and the rear end is connected to the explosion-proof fan.

[0024] The special gas safety cabinet 1 is a dual-cylinder fully automatic gas cylinder cabinet, including a deuterated borane cylinder, a deuterium cylinder, a flow meter, a monitor, a filter, a spray nozzle, etc., mainly used to supply deuterated borane gas to the EAST fusion device and for the storage of special gases. In this embodiment, the special gas safety cabinet 1 is 800 mm long, 500 mm wide, and 2050 mm high, and can accommodate two 40 L steel cylinders. The interior is under negative pressure. When the EAST device chamber is evacuated, the special gas safety cabinet 1 is in the closed state. After the boronization experiment is completed, the B2D6 cylinder is immediately shut off.

[0025] Gas transmission pipeline 2 is an all-metal, double-walled stainless steel conduit. The connections in gas transmission pipeline 2 are sealed using automatic welding. The interlayer of the double-walled pipeline is evacuated to a pressure below 0.01 MPa. This gas transmission pipeline is primarily used for transporting deuterated borane gas. Gas transmission pipeline 2 has an inner pipe dimension of 1 / 4 inch and an outer pipe dimension of 1 / 2 inch. Multiple vacuum shut-off valves are installed above it for isolating and connecting to the gas source. See also... Figure 1 A first vacuum shut-off valve 3a is installed on the gas transport pipeline 2 between the special gas safety cabinet 1 and the gas distribution box 4.

[0026] After the boronizing experiment, in order to remove the residual deuterated borane in the gas transmission pipeline 2, the pipeline was flushed with He three times. After dilution, the concentration of deuterated borane could be reduced to less than 0.1 ppm.

[0027] The gas distribution box 4 is 540 mm long, 300 mm wide, and 1000 mm high. It contains one gas inlet and three gas outlets, connected to the EAST fusion device chamber via a gas transmission pipe 2 with an inner tube size of 1 / 4 inch and an outer tube size of 1 / 2 inch. The three gas outlets are welded and sealed to the CF25 flanges pre-installed at the K, F, and O windows of the EAST device via the gas transmission pipe 2. Figure 1As shown, a second vacuum shut-off valve 3b, a third vacuum shut-off valve 3c, and a fourth vacuum shut-off valve 3d are respectively installed on the three gas transport pipelines 2.

[0028] The surface of the gas distribution box 4 is electropolished. The gas distribution box 4 is made of 316L stainless steel and is used for pressure regulation, gas distribution, and leak cutoff of deuterated borane.

[0029] In this embodiment, the gas monitor 5 is used to monitor the concentration of special gases (deuterated diborane and deuterium) in real time at various locations, including the inside and outside of the special gas safety cabinet 1, the inside and outside of the gas distribution box 4, the EAST fusion device inlet, the vacuum pump unit, and the exhaust gas processor 8. The detection method is pump-suction, and the alarm settings are B2D6 > 0.1 ppm and D2 > 1000 ppm. During and at the end of the boronization experiment, the concentrations of deuterated diborane and deuterium in each part are monitored in real time to ensure the safety of the experiment.

[0030] The safety interlock system primarily monitors the operating status of the special gas safety cabinet 1 and gas distribution box 4, the vacuum status of the gas transmission pipeline 2, the concentration of the gas monitor 5, the status of the exhaust gas processor 8, and the operating status of the vacuum pumping unit. In the event of a fault or alarm, it automatically shuts off the deuterated borane cylinder valve. The safety interlock system has a three-tiered management authority consisting of operators, shift supervisors, and administrators, and features a local red, yellow, and green tri-color audible and visual alarm. In case of a fault, the local emergency shutdown button can be pressed.

[0031] The vacuum pumping unit is mainly used to maintain the concentration of deuterated borane during boronization and to remove it afterward. The vacuum pumping unit is connected to the EAST fusion device chamber via stainless steel piping. It mainly consists of a 500-800 L / s magnetic levitation molecular pump 6 and a 15-25 L / s mechanical dry pump 7. During the initial evacuation of the EAST fusion device chamber, only the mechanical dry pump 7 is activated to provide vacuum pumping capacity. Once the vacuum in the EAST fusion device chamber is sufficient to start the magnetic levitation molecular pump 6, it can be directly activated to obtain a better vacuum environment. The combination of the magnetic levitation molecular pump 6 and the mechanical dry pump 7 is primarily to prevent borane from contacting the oil-containing vacuum pump unit during the deuterated borane supply, which could cause the grease to solidify and lead to malfunctions in the vacuum pump unit. See also... Figure 1 A fifth vacuum shut-off valve 3e is installed between the EAST fusion device chamber and the magnetic levitation molecular pump 6.

[0032] Furthermore, the magnetic levitation molecular pump 6 primarily provides a higher vacuum environment for the vacuum testing chamber. A mechanical dry pump 7 is configured as the pre-pump for the magnetic levitation molecular pump 6. The mechanical dry pump 7 is connected in series with the magnetic levitation molecular pump 6, providing pumping capacity during the initial evacuation of the EAST device and serving as the pre-pump for the molecular pump after the airflow in the EAST device chamber has stabilized.

[0033] The present invention comprises two exhaust gas processors 8, located at the rear end of the special gas safety cabinet 1 and the mechanical dry pump 7. Each exhaust gas processor 8 is connected to the exhaust port of the mechanical dry pump 7 of the vacuum pumping unit via a stainless steel pipe (a sixth vacuum shut-off valve 3f is installed on the connected pipe). Explosion-proof fans are installed at the rear end of each exhaust gas processor 8. The exhaust gas processors are dry adsorption type, with a maximum deuterated borane processing capacity of 3 L / min. During the boronization experiment, they react chemically with the deuterated borane gas to form a solid compound. The concentration of deuterated borane after dilution can be reduced to below 0.1 ppm. Finally, the exhaust gas is discharged normally through the explosion-proof fans.

[0034] The stainless steel pipe of the exhaust gas processor 8 is sealed to the sixth vacuum shut-off valve 3f via a threaded connection, ensuring the vacuum tightness requirements of the exhaust gas discharge pipeline. The sixth vacuum shut-off valve 3f is mainly used to control the inlet and outlet of the exhaust gas and to isolate and connect the EAST device chamber with the downstream exhaust gas processor. During and at the end of the boronizing experiment, the sixth vacuum shut-off valve 3f remains open; at the end of exhaust gas treatment, the sixth vacuum shut-off valve 3f is closed, isolating the EAST device chamber from the downstream exhaust gas processor. The exhaust gas processor is a dry adsorption type, used to chemically react with deuterated borane gas to form a solid compound, and is connected to an explosion-proof fan at the rear; after sufficient treatment of the exhaust gas, it is discharged through the explosion-proof fan.

[0035] The specific workflow of the boronization system for the first wall treatment of the EAST fusion device is as follows: First, open the fifth vacuum shut-off valve 3e and the sixth vacuum shut-off valve 3f in the system, and close the first vacuum shut-off valve 3a, the second vacuum shut-off valve 3b, the third vacuum shut-off valve 3c, and the fourth vacuum shut-off valve 3d. Then, turn on the mechanical dry pump 7 to evacuate the vacuum level of the EAST device chamber to about 10 Pa. Finally, turn on the magnetic levitation molecular pump 6 to evacuate the vacuum level of the EAST device chamber to 10 Pa. -6Below the level; then open the first vacuum shut-off valve 3a, allowing the deuterated borane gas in the special gas safety cabinet 1 to be transferred to the gas distribution box 4 through the gas transmission pipeline 2. After pressure regulation and diversion in the gas distribution box 4, the second vacuum shut-off valve 3b, the third vacuum shut-off valve 3c, and the fourth vacuum shut-off valve 3d are then opened, allowing the gas to enter the EAST device chamber from windows F, K, and O respectively through the gas transmission pipeline 2. The gas monitor 5 monitors the borane content in real time at the inside and outside of the special gas safety cabinet 1, the inside and outside of the gas distribution box 4, the EAST device inlet, the vacuum pump unit, and the tail gas processor 8. After the experiment, the deuterated borane gas source in the special gas safety cabinet 1 is shut off, and the He gas cylinder is opened to flush the system multiple times. The borane gas in the special gas safety cabinet 1 and the gas transmission pipeline 2 reacts chemically with the deuterated borane gas in the tail gas processor 8 to form a solid compound. The concentration of deuterated borane after dilution can be reduced to 0.1%. The concentration is below ppm, and then discharged into the atmosphere via an explosion-proof fan, thus completing the operation process of the boronizing treatment system for the first wall surface of the EAST fusion device.

[0036] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0037] The parts of this invention not described in detail are well-known in the art. The above embodiments are provided merely for the purpose of describing the invention and are not intended to limit its scope. The scope of the invention is defined by the appended claims. All equivalent substitutions and modifications made without departing from the spirit and principles of the invention should be covered within its scope.

Claims

1. A system for boronization of a first wall surface of a fusion device, the system comprising: a boronization chamber; a boron source; a plasma source; and a plasma generator. The system comprises a special gas safety cabinet, a gas transmission pipeline, a gas distribution box, a safety interlocking system, a vacuum air extractor set and a tail gas processor; the special gas safety cabinet is connected with the gas distribution box through the gas transmission pipeline; the gas distribution box is connected with a vacuum chamber of an EAST fusion device through the gas transmission pipeline; the safety interlocking system is used for detecting the running states of the special gas safety cabinet, the gas distribution box, the vacuum air extractor set and the tail gas processor; the vacuum air extractor set is connected with the EAST fusion device; and the tail gas processor is connected with an exhaust port of a mechanical dry pump of the vacuum air extractor set.

2. The system for boronization of first wall surfaces of a fusion device according to claim 1, wherein, The special gas safety cabinet is used for supplying a deuterated diborane gas source and storing special gas to the EAST fusion device, and the special gas safety cabinet is a double-bottle full-automatic gas cylinder cabinet, and the whole special gas safety cabinet is in a negative pressure state.

3. The system for boronization of first wall surfaces of a fusion device of claim 1, wherein, The gas transmission pipeline is used for transporting the deuterated diborane gas, and the gas transmission pipeline adopts a full-metal double-layer containing stainless steel pipeline, and the interlayer position of the double-layer pipeline is vacuumized to 0.01 MPa or less; and the connection position of the gas transmission pipeline is sealed by using an automatic welding mode.

4. The system for boronization of first wall surfaces of a fusion device according to claim 3, wherein, The inner tube size of the gas transmission pipeline is 1 / 4 inch, and the outer tube size is 1 / 2 inch.

5. The system for boronization of first wall surfaces of a fusion device of claim 1, wherein, The gas distribution box is located near the EAST fusion device, an air path inlet and three air path outlets are arranged in the gas distribution box, and the gas distribution box is used for supplying and flow control of the deuterated diborane gas to three positions of the EAST fusion device after the deuterated diborane gas is introduced from the special gas safety cabinet.

6. The system for boronization of first wall surfaces of a fusion device of claim 1, wherein, The system for the boronization treatment system of the first wall surface of the fusion device further comprises a gas monitor, the gas monitor is used for detecting the concentration of the special gas, and the gas monitor is arranged on the inside and outside of the special gas safety cabinet, the inside and outside of the gas distribution box, the inlet of the EAST fusion device, the vacuum air extractor set and the tail gas processor.

7. The system for boronization of first wall surfaces of a fusion device according to claim 6, wherein The detection mode of the gas monitor is a pump suction type, and the alarm setting value of the gas monitor is B2D6>0.1 ppm and D2>1000 ppm.

8. The system for boronization of first wall surfaces of a fusion device of claim 1, wherein, The vacuum air extractor set is used for maintaining the deuterated diborane concentration during boronization and removing the deuterated diborane after the boronization is completed, and the vacuum air extractor set comprises a magnetic suspension molecular pump and a mechanical dry pump.

9. The system for boronization of first wall surfaces of a fusion device according to claim 8, wherein, The pumping speed of the magnetic suspension molecular pump is 500-800 L / s, and the pumping speed of the mechanical dry pump is 15-25 L / s.

10. The system for boronization of first wall surfaces of a fusion device of claim 1, wherein, The tail gas processor is a dry adsorption type, and the maximum processing capacity of the tail gas processor for the deuterated diborane is 3 L / min.

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