CN104602439A - Rotation tritium target device cooled by gallium-indium liquid metal - Google Patents

Abstract

The invention provides a rotating tritium target device cooled by gallium indium liquid metal, comprising a vacuum rotating hollow shaft, a rotating tritium target piece, a cooling structure, a pneumatic turbine transmission mechanism, a vacuum pumping pipeline, an accelerator interface, a beam cooling spiral tube, Gallium indium liquid metal cooling circulation system. This invention can be used as a rotating tritium target system for high-current deuterium-tritium fusion neutron generators. It uses gallium indium liquid metal with high thermal conductivity and atomic number at room temperature to replace the current cooling medium water used as the cooling of the rotating tritium target. The medium can not only greatly improve the cooling effect of the target, but also reduce the impact of the backscattering of atoms in the cooling medium on the energy and intensity of the neutrons emitted by the target, and effectively improve the neutrons emitted by the tritium target system of the neutron generator. monochromaticity.

Description

A rotating tritium target device cooled by gallium indium liquid metal

technical field

The invention relates to a rotating tritium target device cooled by gallium indium liquid metal, which is mainly used for high-flux deuterium-tritium fusion neutron generator rotating tritium target system to generate high-flux deuterium-tritium fusion neutron beams, which can be used in neutron physics, Research fields such as medical physics, radiation protection and nuclear technology applications play an important role.

Background technique

The deuterium-tritium fusion neutron generator uses a strong deuterium ion beam to bombard a tritium target to generate a 14MeV high-energy fusion neutron.

The bombardment of the high-current ion beam will deposit a large amount of heat on the tritium target of the neutron generator, and the instantaneous heat flux can reach up to about tens of kW/cm ² , while the thickness of the titanium film part absorbing tritium on the tritium target is only a few μm, if the above-mentioned heat cannot be quickly discharged through the circulating cooling medium of the target substrate in a short time, the temperature of the target will be too high. Once the surface temperature of the target exceeds 200°C, a large amount of tritium in the target will escape and be lost. Even cause the diameter of the target piece to burn.

At present, the high-current neutron generators at home and abroad generally adopt the forced water-cooled large-area high-speed rotating tritium-titanium target system with high tritium content. A circular or spherical crown-shaped target is adopted, on which the tritium-containing titanium film is distributed in the shape of a ring. The target has a large area and a diameter of more than 20 cm. It can rotate around its central axis at high speed, and the speed is generally 1000-5000 rpm. minute. When working, the incident direction of the deuterium ion beam remains unchanged, and the tritium-titanium film ring belt on the rotating target is uniformly bombarded in turn, and at the same time, a high-speed circulating cooling water with a flow rate of 20-30 liters per minute is passed through the bottom of the target, so that the basic It is guaranteed that the target will not be overheated to cause tritium release loss, and the target will not be burned; however, this cooling method will have a certain impact on the monochromaticity of the outgoing neutrons due to the introduction of cooling water flow to the target substrate. In addition, the practical experience shows that due to the limitation of water heat transfer performance and the mechanical structure and strength of the rotating target, the further improvement of the incident deuterium ion beam intensity and the neutron intensity of the deuterium-tritium reaction is limited. The present invention replaces water with gallium indium liquid metal at normal temperature as the cooling medium, because the thermal conductivity of liquid metal reaches 10-50W/m·K, which is dozens of times that of water, and the working temperature range is 0°C to 2000°C, using liquid metal High thermal conductivity can more effectively increase the heat transfer of the target substrate and enhance the heat transfer effect; at the same time, due to the high atomic number of gallium and indium, it can further reduce the influence of the cooling medium on the neutron monochromaticity of the target. .

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a rotating tritium target device cooled by gallium indium liquid metal, which is used in high-flux deuterium-tritium fusion neutron generator rotating tritium target system sub-bundle.

The technical scheme adopted in the present invention is: a rotating tritium target device cooled by gallium indium liquid metal, including a rotating tritium target body and a gallium indium liquid metal circulation cooling system, the rotating tritium target body is composed of a vacuum rotating hollow shaft, a rotating tritium target piece , cooling structure, pneumatic turbine transmission mechanism, vacuum pumping pipeline, accelerator interface, and beam cooling spiral tube. The gallium indium liquid metal circulation cooling system is composed of pipeline, water-cooled condensing unit, and electromagnetic pump. Among them, the rotating tritium target plate It is fixed together with the vacuum rotating hollow shaft through threaded connection for high-speed rotating motion. The pneumatic turbine transmission mechanism is installed on the vacuum rotating hollow shaft with blades. Compressed air is used to realize the high-speed rotation of the rotating tritium target and the vacuum rotating hollow shaft. The speed can be adjusted. Up to 3500rpm, the cooling structure is composed of baffles, cooling medium inlets, cooling medium outlets, and mechanical seals. Gallium indium liquid metal enters the cooling structure to cool the target, and then circulates into the rotating tritium after cooling through the gallium indium liquid metal circulation cooling system. target subject.

Among them, gallium-indium liquid metal with high thermal conductivity and atomic number is used instead of traditional water as the cooling medium of the rotating tritium target, while effectively improving the heat dissipation of the rotating tritium target, due to the high atomic numbers of gallium and indium, further To reduce the influence of the cooling medium on the monochromaticity of neutrons emitted by the target, the gallium indium liquid metal flows in from the cooling medium inlet driven by the electromagnetic pump and sprays on the back of the rotating tritium target, and then falls back under the action of gravity, self-cooling medium After the outlet flows out, it enters the gallium indium liquid metal circulation cooling system. After being refrigerated by the water-cooled condensing unit, it circulates into the cooling structure under the drive of the electromagnetic pump to cool the rotating tritium target.

Among them, the high-energy and high-intensity deuterium beam generated by the accelerator passes through the accelerator interface, the vacuum rotating hollow shaft, and the beam cooling spiral tube, and then bombards the rotating tritium target. Under the protection of the beam cooling spiral tube, the scattered deuterium beam is effectively prevented. The air flow bombards on the vacuum rotating hollow shaft, causing the temperature to be too high, resulting in the failure of the pneumatic turbine transmission mechanism.

Among them, the gallium indium liquid metal is sprayed on the back of the rotating tritium target after flowing in from the cooling medium inlet driven by the electromagnetic pump, and then falls back under the action of gravity, and enters the gallium indium liquid metal circulation cooling system after flowing out from the cooling medium outlet. After being refrigerated by the water-cooled condensing unit, it circulates into the cooling structure under the drive of the electromagnetic pump to cool the rotating tritium target. The mechanical seal realizes the dynamic sealing of the liquid metal between the cooling structure and the vacuum rotating hollow shaft to prevent the liquid metal from leaking out. The high-energy, high-intensity deuterium beam generated by the accelerator passes through the accelerator interface, the vacuum rotating hollow shaft, and the beam cooling spiral tube, and then bombards the rotating tritium target. Under the protection of the beam cooling spiral tube, the scattered deuterium beam can be effectively prevented The air flow bombards on the vacuum rotating hollow shaft, causing the temperature to be too high, which affects the normal operation of the pneumatic turbine transmission mechanism and other components. The vacuum rotating hollow shaft is pumped in real time by using the vacuum pumping pipeline, so that the vacuum rotating hollow shaft always maintains the vacuum degree required for the deuterium beam transmission.

The invention has the advantages that: under the same target area and rotating speed, the heat transfer effect can be improved more effectively by utilizing the higher thermal conductivity of gallium indium liquid metal; at the same time, the effect of the cooling medium on the neutron monochromaticity of the target can be reduced. Influence, improve the accuracy of experimental data and measurement precision. At the same time, the high-energy, high-intensity deuterium beam bombards the rotating tritium target after passing through the accelerator interface, the vacuum rotating hollow shaft, and the beam cooling spiral tube. The beam cooling spiral tube is used to effectively prevent the scattered deuterium beam from bombarding the vacuum rotating hollow. On the shaft, the temperature is too high, causing the failure of the pneumatic turbine transmission mechanism and other components.

Description of drawings

Figure 1 is a structural diagram of a rotating tritium target device cooled by gallium indium liquid metal.

The meanings of the marks in the figure are:

1. Cooling medium outlet; 2. Cooling medium inlet; 3. Rotating tritium target body; 4. Cooling structure; 5. Rotating tritium target piece; 6. Baffle plate; 7. Mechanical seal; 8. Vacuum rotating hollow shaft; 9. Air bearing air inlet; 10. Radial bearing air inlet; 11. Thrust bearing air inlet; 12. Pneumatic turbine exhaust cavity; 13. Pneumatic turbine exhaust pipe; 14. Pneumatic turbine transmission mechanism; 15. Pneumatic turbine Intake cavity; 16. Pneumatic turbine intake pipe; 17. Air bearing air inlet; 18. Air bearing air intake ring cavity; 19. Radial air bearing exhaust outlet; 20. Air bearing exhaust port; 21. Vacuum pumping Gas pipeline; 22. Accelerator interface; 23. Deuterium beam; 24. Beam cooling spiral tube; 25. Inlet and outlet of beam cooling spiral tube; 26. Pipeline; 27. Gallium indium liquid metal circulation cooling system; 28. Water cooling Type condensing unit; 29. Electromagnetic pump.

Detailed ways

In order to enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

1. Vacuum rotating hollow shaft 8: its interior is evacuated, one end is connected with the rotating target with screws, and the other end is connected with the accelerator interface. The vacuum rotating hollow shaft 8 rotates with the rotating tritium target 5 at a speed of 3500rpm, and the vacuum rotating hollow shaft The dynamic seal between 8 and the accelerator interface 22 is realized by real-time vacuum pumping through the vacuum pumping pipeline 21 to ensure the vacuum degree in the cavity.

2. Rotating tritium target piece 5: The rotating tritium target piece 5 uses copper alloy as the base and is made into a spherical crown shape. The inner surface of the spherical crown shape is coated with a metal titanium film. In a high temperature environment, the titanium film absorbs tritium, and the deuterium beam flows from the interface. The flange is incident and bombarded on: the rotating tritium target piece 5, deuterium and tritium react to produce neutrons, and the neutrons diverge to the surroundings; the rotating tritium target piece 5 and the vacuum rotating hollow shaft 8 are fixed with screws, at 3500rpm Rotating at a high speed, the deuterium beam bombards the target off-center, causing the heated part of the target to change continuously, avoiding the high-energy beam bombardment that makes the temperature of the rotating tritium target 5 too high, resulting in a large amount of tritium release.

3. Cooling structure 4: The cooling structure 4 is composed of a baffle plate 6, a cooling medium inlet 2, a cooling medium outlet 1, and a mechanical seal 7. Gallium indium liquid metal flows in from the cooling medium inlet 2 and sprays on the back of the rotating tritium target 5, Then it falls back under the action of gravity, flows out from the cooling medium outlet 1, and then circulates into the rotating tritium target body 3 after dissipating heat through the gallium indium liquid metal circulation cooling system 27. The mechanical seal 7 can realize the fixed cooling structure 4 and the vacuum rotating hollow shaft The dynamic seal between 8 prevents the leakage of the cooling medium, and is generally applicable to occasions where the rotational speed is tens of m/s.

4. Gallium indium liquid metal circulating cooling system 27: Gallium indium liquid metal flows in from the cooling medium inlet 2 under the drive of the electromagnetic pump 29 and sprays on the back of the rotating tritium target piece 5, then falls back under the action of gravity, and flows from the cooling medium outlet 1 flows out and enters the gallium indium liquid metal circulation cooling system 27, and after being refrigerated by the water-cooled condensing unit 28, it circulates into the cooling structure 4 under the drive of the electromagnetic pump 29 to cool the target.

5. Pneumatic turbine transmission mechanism 14: This device is a device that converts the pressure energy of compressed air into mechanical energy. The compressed air enters the sealed air turbine intake chamber 15 through the air turbine intake pipe 16 and acts on the vacuum rotating hollow shaft 8. Due to the different protruding lengths of the blades, a torque difference is generated, so that the rotating shaft rotates in one direction, and the compressed air is discharged through the air turbine exhaust chamber 12 and the air turbine exhaust pipe 13. The air turbine transmission mechanism 14 It can realize the high-speed rotation of the rotating shaft and the target piece at 3500rpm.

Claims (4)

1. A rotating tritium target device cooled by gallium indium liquid metal, comprising a rotating tritium target body (3) and a gallium indium liquid metal circulation cooling system (27), characterized in that: the rotating tritium target body (3) is rotated by a vacuum Hollow shaft (8), rotating tritium target (5), cooling structure (4), pneumatic turbine transmission mechanism (14), vacuum pumping pipe (21), accelerator interface (22), beam cooling spiral tube (24) The gallium indium liquid metal circulating cooling system (27) is composed of a pipeline (26), a water-cooled condensing unit (28), and an electromagnetic pump (29), wherein the rotating tritium target (5) and the vacuum rotating hollow shaft (8 ) are fixed together by threaded connection for high-speed rotation, the pneumatic turbine transmission mechanism (14) is installed on the vacuum rotating hollow shaft (8) with blades, and compressed air is used to realize the rotation of the tritium target piece (5) and the vacuum rotating hollow shaft ( 8) The high-speed rotation, the speed reaches 3500rpm, the cooling structure (4) is composed of the baffle (6), the cooling medium inlet (2), the cooling medium outlet (1), and the mechanical seal (7), and the gallium indium liquid metal enters the cooling structure In (4), the target piece is cooled, and then circulated into the rotating tritium target body (3) after dissipating heat through the gallium indium liquid metal circulation cooling system (27). 2. A rotating tritium target device cooled by gallium indium liquid metal according to claim 1, characterized in that: the gallium indium liquid metal with higher thermal conductivity and atomic number is used instead of traditional water as the rotating tritium target (5 ) cooling medium, while effectively improving the heat dissipation of the rotating tritium target (5), because the atomic numbers of gallium and indium are higher, the influence of the cooling medium on the neutron monochromaticity of the target is further reduced, and the gallium indium liquid metal Driven by the electromagnetic pump (29), it flows in from the cooling medium inlet (2) and sprays on the back of the rotating tritium target (5), then falls back under the action of gravity, and enters the gallium indium liquid state after flowing out from the cooling medium outlet (1). The metal circulating cooling system (27), after being refrigerated by the water-cooled condensing unit (28), circulates into the cooling structure (4) under the drive of the electromagnetic pump (29) to cool the rotating tritium target piece (5). 3. A rotating tritium target device cooled by gallium indium liquid metal according to claim 1, characterized in that: the deuterium beam (23) of high energy and high current intensity produced by the accelerator passes through the accelerator interface (22), vacuum rotation After the hollow shaft (8) and the beam cooling helical tube (24) bombard the rotating tritium target (5), under the protection of the beam cooling helical tube (24), the scattered deuterium beam (23) is effectively prevented from bombarding the vacuum On the rotating hollow shaft (8), the temperature is too high, causing the failure of the pneumatic turbine transmission mechanism (14). 4. A rotating tritium target device cooled by gallium indium liquid metal according to claim 1, characterized in that the gallium indium liquid metal is sprayed on the rotating tritium target after being driven by an electromagnetic pump from the inlet of the cooling medium. On the back side, it falls back under the action of gravity, flows out from the outlet of the cooling medium, and enters the gallium indium liquid metal circulation cooling system. After being refrigerated by the water-cooled condensing unit, it circulates into the cooling structure driven by the electromagnetic pump to carry out the rotation of the tritium target. Cooling, mechanical seal realizes the dynamic sealing of liquid metal between the cooling structure and the vacuum rotating hollow shaft, preventing liquid metal from leaking out. The high-energy, high-intensity deuterium beam generated by the accelerator passes through the accelerator interface, the vacuum rotating hollow shaft, and beam cooling The helical tube bombards the rotating tritium target piece afterward. Under the protection of the beam cooling helical tube, it can effectively prevent the scattered deuterium beam from bombarding the vacuum rotating hollow shaft, causing the temperature to be too high and affecting the normal operation of the pneumatic turbine transmission mechanism and other components. In operation, use the vacuum pumping pipeline to carry out real-time pumping of the vacuum rotating hollow shaft, so that the vacuum rotating hollow shaft always maintains the vacuum degree required for the transmission of the deuterium beam.