Helium cryogenic cycle system for deuterium-tritium fusion device

Abstract

The application relates to a helium cryogenic circulating system for a deuterium-tritium fusion device, which comprises a first heat exchanger, a second heat exchanger, a third heat exchanger, a fifth heat exchanger and a first compressor; a high-temperature helium pipe is connected with a first inlet of the first heat exchanger; a first outlet of the first heat exchanger is connected with an inlet of the first compressor; an outlet of the first compressor is connected with an inlet of the fifth heat exchanger; an outlet of the fifth heat exchanger is connected with a second inlet of the first heat exchanger; a second outlet of the first heat exchanger is connected with a first inlet of the second heat exchanger; a first outlet of the second heat exchanger is connected with an inlet of the third heat exchanger; and an outlet of the third heat exchanger is connected with a low-temperature helium pipe. The helium cryogenic circulating system for the deuterium-tritium fusion device can provide stable 80K temperature zone helium active cooling supply for a deuterium-tritium fusion reactor through the cooperation of multi-stage heat exchangers and compressors.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of refrigeration technology, and in particular to a helium cryogenic circulation system for a deuterium-tritium fusion device. BACKGROUND

[0002] With the increasing demand for energy, controlled nuclear fusion is considered as a solution for clean energy in the future. The principle is to simulate the nuclear fusion process inside the sun, that is, to make light atomic nuclei (such as deuterium and tritium) undergo fusion under extremely high temperature and pressure, and release huge energy.

[0003] In order to ensure the stable operation of the fusion device, active cooling of 80K temperature zone needs to be provided for all components of the fusion reactor device with cold screens, including: deuterium-tritium fusion reactor main machine inner and outer cold screens, vacuum chamber cryogenic pump, NBI cryogenic pump, feeder cold screen, cryogenic distribution valve box, cryogenic transmission pipeline and other components.

[0004] However, due to the strong penetration of high-energy neutrons generated by deuterium-tritium (D-T) fusion reaction, if traditional liquid nitrogen is used as the cooling medium, high-energy neutrons will activate nitrogen nuclei and produce radioactive isotopes, resulting in contamination of the cooling circuit and affecting the system life and maintenance. Therefore, in order to avoid the problem of nitrogen activation, helium becomes an ideal cooling medium: its inert single-atom characteristics make it not react with neutrons, avoiding radioactive contamination; it remains stable in gaseous state at 80K temperature zone, meeting the low-temperature cooling demand and having no phase change risk; it has excellent material compatibility and does not corrode mechanical structure materials; in addition, helium gas is easy to purify and recover after leakage, with low operation and maintenance cost, meeting the long-period operation demand of the fusion reactor.

[0005] Therefore, a stable helium cryogenic circulation system for a deuterium-tritium fusion device is provided. SUMMARY

[0006] To solve the above technical problems, the present application provides a helium cryogenic circulation system for a deuterium-tritium fusion device. The low-temperature circulation system provides stable 80K temperature zone helium cooling for the fusion reactor through the synergistic effect of multi-stage heat exchangers and compressors.

[0007] To achieve the above purpose, the present application adopts the following technical solutions:

[0008] A helium cryogenic circulation system for a deuterium-tritium fusion device, comprising a first heat exchanger, a second heat exchanger, a third heat exchanger, a fifth heat exchanger and a first compressor;

[0009] The high-temperature helium pipe is connected with the first inlet of the first heat exchanger, the first outlet of the first heat exchanger is connected with the inlet of the first compressor, the outlet of the first compressor is connected with the inlet of the fifth heat exchanger, the outlet of the fifth heat exchanger is connected with the second inlet of the first heat exchanger, the second outlet of the first heat exchanger is connected with the first inlet of the second heat exchanger, the first outlet of the second heat exchanger is connected with the inlet of the third heat exchanger, and the outlet of the third heat exchanger is connected with the low-temperature helium pipe.

[0010] The third heat exchanger is immersed in the liquid nitrogen tank.

[0011] The helium low-temperature circulation system for the deuterium-tritium fusion device further comprises a liquid nitrogen re-liquefaction device, the liquid nitrogen re-liquefaction device comprises a second compressor, a sixth heat exchanger, a fourth heat exchanger, an expander and a second gas-liquid separator, the outlet of the liquid nitrogen tank is connected with the inlet of the second compressor, the outlet of the second compressor is connected with the inlet of the sixth heat exchanger, the outlet of the sixth heat exchanger is connected with the second inlet of the fourth heat exchanger, the second outlet of the fourth heat exchanger is connected with the inlet of the expander, the outlet of the expander is connected with the inlet of the second gas-liquid separator, and the first outlet of the second gas-liquid separator is connected with the first inlet of the liquid nitrogen tank.

[0012] Preferably, the second outlet of the second gas-liquid separator is connected with the first inlet of the fourth heat exchanger, and the first outlet of the fourth heat exchanger is connected with the inlet of the second compressor.

[0013] Preferably, the liquid nitrogen re-liquefaction device further comprises a first gas-liquid separator, the first outlet of the second gas-liquid separator is connected with the second inlet of the second heat exchanger, the second outlet of the second heat exchanger is connected with the inlet of the first gas-liquid separator, and the first outlet of the first gas-liquid separator is connected with the second inlet of the liquid nitrogen tank.

[0014] Preferably, the second outlet of the first gas-liquid separator is connected with the inlet of the second compressor.

[0015] Preferably, the temperature of the second outlet of the second heat exchanger is always higher than the dew point temperature of nitrogen gas at the pressure thereof.

[0016] Preferably, a fourth adjusting valve is arranged between the first outlet of the second gas-liquid separator and the second inlet of the second heat exchanger, and the amount of liquid nitrogen flowing through the second inlet of the second heat exchanger is regulated by adjusting the fourth adjusting valve.

[0017] The low-temperature pump return pipe is connected with the third inlet of the first heat exchanger, and the third outlet of the first heat exchanger is connected with the inlet of the first compressor.

[0018] Preferably, the fifth heat exchanger and the sixth heat exchanger are water-cooled heat exchangers.

[0019] The beneficial effects of the present application are as follows:

[0020] (1) The helium cryogenic circulation system for a deuterium-tritium fusion device of the present application provides stable 80K temperature zone helium gas active cooling supply for the fusion reactor through the joint action of the multi-stage heat exchanger and the compressor.

[0021] (2) The helium cryogenic circulation system for a deuterium-tritium fusion device of the present application, through the synergistic action of the multi-stage heat exchanger, the compressor and the liquid nitrogen reliquefaction device, uses helium gas as the cooling medium to avoid neutron activation pollution, and integrates the cold energy recovery and nitrogen reliquefaction functions, significantly improving the cooling efficiency and energy utilization rate, and being suitable for long-period reliable operation of the deuterium-tritium fusion reactor.

[0022] (3) The helium cryogenic circulation system for a deuterium-tritium fusion device of the present application dynamically adjusts the liquid nitrogen flow to maintain the system temperature stable. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The figure is a schematic diagram of the overall structure of the helium cryogenic circulation system for a deuterium-tritium fusion device of the present application.

[0024] The figure is a schematic diagram of the overall structure of the helium cryogenic circulation system for a deuterium-tritium fusion device of the present application. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application 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 only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0026] Reference Figure 1 A helium cryogenic circulation system for a deuterium-tritium fusion device, comprising a first heat exchanger 1, a second heat exchanger 2, a third heat exchanger 3, a fifth heat exchanger 9 and a first compressor 8; a high-temperature helium gas pipe is connected to a first inlet 1A of the first heat exchanger, a first outlet 1B of the first heat exchanger is connected to an inlet of the first compressor 8, an outlet of the first compressor 8 is connected to an inlet of the fifth heat exchanger 9, an outlet of the fifth heat exchanger 9 is connected to a second inlet 1C of the first heat exchanger, a second outlet 1D of the first heat exchanger is connected to a first inlet 2B of the second heat exchanger, a first outlet 2A of the second heat exchanger is connected to an inlet 3A of the third heat exchanger, and an outlet 3B of the third heat exchanger is connected to a low-temperature helium gas pipe.

[0027] Preferably, the second heat exchanger 2 is preferably made of stainless steel, the third heat exchanger 3 is a thermosyphon heat exchanger, and the fifth heat exchanger 9 and the sixth heat exchanger 11 are water-cooled heat exchangers.

[0028] Preferably, a high-temperature low-pressure helium gas pipe is connected to an inlet of the first regulating valve V1, an outlet of the first regulating valve V1 is connected to the first inlet 1A of the first heat exchanger, the first outlet 1B of the first heat exchanger is connected to the inlet of the first compressor 8, the outlet of the first compressor 8 is connected to the inlet of the fifth heat exchanger 9, the outlet of the fifth heat exchanger 9 is connected to the second inlet 1C of the first heat exchanger, the second outlet 1D of the first heat exchanger is connected to the first inlet 2B of the second heat exchanger, the first outlet 2A of the second heat exchanger is connected to the inlet 3A of the third heat exchanger, the outlet 3B of the third heat exchanger is connected to the inlet of the second regulating valve V2, and the outlet of the second regulating valve V2 is connected to the low-temperature helium gas pipe to supply low-temperature high-pressure helium gas.

[0029] The operation flow is as follows: 100K temperature zone low pressure helium gas supplied by the user end enters the first heat exchanger 1, and after the cold energy recovery is completed in the heat exchanger, the helium gas temperature is raised to room temperature through the first outlet 1B of the first heat exchanger, and then the room temperature helium gas enters the first compressor 8 through the inlet of the first compressor 8, and the pressure of the helium gas is raised to the rated value through compression. In order to eliminate the temperature rise effect caused by the work and compression of the first compressor 8 on the helium gas, the high pressure helium gas is cooled to room temperature through the fifth heat exchanger 9 by cooling water, and then the room temperature helium gas is introduced into the second inlet 1C of the first heat exchanger in the cold box, and then the helium gas is heat-exchanged to the 100K temperature zone, and then cooled to the 90K temperature zone through the first inlet 2B of the second heat exchanger cooled by liquid nitrogen, and then cooled to the 80K temperature zone through the third heat exchanger 3, and then transported back to the user end. The above-mentioned heat exchange process realizes the cooling of the 100K temperature zone low pressure helium gas to the 80K temperature zone high pressure helium gas.

[0030] Referring to Figure 1 In one embodiment, the third heat exchanger 3 is immersed in the liquid nitrogen tank 5, and the purpose is to ensure the stability of the gas temperature at the outlet 3B of the third heat exchanger.

[0031] As a preferred embodiment, the helium low-temperature circulation system for the deuterium-tritium fusion device further comprises a liquid nitrogen re-liquefaction device, and the liquid nitrogen re-liquefaction device comprises a second compressor 10, a sixth heat exchanger 11, a fourth heat exchanger 7, an expander 12 and a second gas-liquid separator 6. The outlet 5C of the liquid nitrogen tank is connected to the inlet of the second compressor 10, the outlet of the second compressor 10 is connected to the inlet of the sixth heat exchanger 11, the outlet of the sixth heat exchanger 11 is connected to the second inlet 7C of the fourth heat exchanger, the second outlet 7D of the fourth heat exchanger is connected to the inlet of the expander 12, the outlet of the expander 12 is connected to the inlet of the second gas-liquid separator 6, and the first outlet 6A of the second gas-liquid separator is connected to the first inlet 5A of the liquid nitrogen tank.

[0032] When the liquid level of the liquid nitrogen in the liquid nitrogen tank 5 is too low, the high temperature and high pressure liquid nitrogen in the second gas-liquid separator 6 is throttled through the third throttle valve J3, and then the low temperature and low pressure liquid nitrogen flows into the liquid nitrogen tank 5.

[0033] As a preferred embodiment, the second outlet 6B of the second gas-liquid separator is connected to the first inlet 7A of the fourth heat exchanger, and the first outlet 7B of the fourth heat exchanger is connected to the inlet of the second compressor 10.

[0034] Referring to Figure 1 The first outlet 6A of the second gas-liquid separator is connected to the inlet of the third throttle valve J3, and the outlet of the third throttle valve J3 is connected to the first inlet 5A of the liquid nitrogen tank.

[0035] The second outlet 6B of the second gas-liquid separator is connected with the inlet of the fifth regulating valve V5, and the outlet of the fifth regulating valve V5 is connected with the first inlet 7A of the fourth heat exchanger.

[0036] Preferably, the liquid nitrogen re-liquefaction device further comprises a first gas-liquid separator 4, the first outlet 6A of the second gas-liquid separator is connected with the second inlet 2C of the second heat exchanger, the second outlet 2D of the second heat exchanger is connected with the inlet of the first gas-liquid separator 4, and the first outlet 4B of the first gas-liquid separator is connected with the second inlet 5B of the liquid nitrogen tank. In this way, the helium in the second heat exchanger can be cooled.

[0037] The second outlet 2D of the second heat exchanger is connected with the inlet of the first gas-liquid separator 4, and when the liquid level of the high-temperature and high-pressure liquid nitrogen in the first gas-liquid separator 4 is too high, the low-temperature and low-pressure liquid nitrogen flows into the liquid nitrogen tank 5 after throttling by the first throttling valve J1.

[0038] Referring to Figure 1 , the first outlet 6A of the second gas-liquid separator is connected with the inlet of the fourth regulating valve V4, the outlet of the fourth regulating valve V4 is connected with the second inlet 2C of the second heat exchanger, the second outlet 2D of the second heat exchanger is connected with the inlet of the first gas-liquid separator 4, the first outlet 4B of the first gas-liquid separator is connected with the inlet of the first throttling valve J1, and the outlet of the first throttling valve J1 is connected with the second inlet 5B of the liquid nitrogen tank.

[0039] More preferably, the second outlet 4A of the first gas-liquid separator is connected with the inlet of the second throttling valve J2, and the outlet of the second throttling valve J2 is connected with the inlet of the second compressor 10.

[0040] The low-pressure nitrogen gas from the second throttling valve J2 outlet, the liquid nitrogen tank 5 outlet, and the first outlet 7B of the fourth heat exchanger is pressurized by the second compressor 10, forms high-temperature and high-pressure nitrogen gas, is cooled to room temperature by the sixth heat exchanger 11 through cooling water, is connected to the second inlet 7C of the fourth heat exchanger, is heat-exchanged by the fourth heat exchanger 7 to become low-temperature and high-pressure nitrogen gas, is expanded by the expander 12 to become low-temperature and low-pressure gas, is throttled and cooled by the fourth throttling valve J4, and then flows into the second gas-liquid separator 6.

[0041] Preferably, the temperature of the second outlet 2D of the second heat exchanger is always higher than the dew point temperature of nitrogen gas at its pressure. More preferably, a fourth regulating valve V4 is arranged between the first outlet 6A of the second gas-liquid separator and the second inlet 2C of the second heat exchanger, the amount of liquid nitrogen flowing through the second inlet 2C of the second heat exchanger is regulated by adjusting the fourth regulating valve V4, and the required amount of liquid nitrogen is calculated based on the cooling load required by the second heat exchanger 2.

[0042] Definition: Second heat exchanger hot end (helium gas): inlet temperature , inlet pressure , outlet temperature , outlet pressure , mass flow rate ;

[0043] Second heat exchanger cold end (liquid nitrogen): inlet temperature , inlet pressure , outlet temperature , outlet pressure , mass flow rate ;

[0044] According to the query property parameter database of each inlet and outlet temperature and pressure, the enthalpy values of each point are as follows:

[0045] Second heat exchanger hot end (helium gas): inlet enthalpy value , outlet enthalpy value ;

[0046] Second heat exchanger cold end (liquid nitrogen): inlet enthalpy value , outlet enthalpy value ;

[0047] According to , the cold load required by the second heat exchanger 2 is calculated;

[0048] Then .

[0049] By adjusting the amount of liquid nitrogen flowing through the second inlet 2C of the second heat exchanger , the temperature of the first outlet 2A of the second heat exchanger, i.e. the inlet 3A of the third heat exchanger, is controlled to be the rated value, while ensuring that the liquid level of the liquid nitrogen tank 5 remains stable, thereby ensuring that the temperature of the inlet 3A of the third heat exchanger and the outlet 3B of the third heat exchanger always remains at the rated value.

[0050] Since the helium gas transported by the system during the regeneration process of the cryogenic pump in the deuterium-tritium fusion reactor will eventually flow into the helium recovery system of other systems and not return to the system, it will cause certain flow fluctuations in the system. To avoid temperature fluctuations at the outlet 3B of the third heat exchanger, the amount of liquid nitrogen flowing through the second inlet 2C of the second heat exchanger needs to be adjusted by adjusting the fourth regulating valve V4, and the required amount of liquid nitrogen is calculated from the cold load required by the second heat exchanger 2. Therefore, the temperature of the second outlet 2D of the second heat exchanger is set to be always higher than the dew point temperature of nitrogen at its pressure, and the amount of liquid flowing into the first inlet 5A of the liquid nitrogen tank 5 is adjusted by adjusting the third throttle valve J3 to keep the liquid level of the liquid nitrogen tank 5 stable, thereby ensuring the temperature stability of the first outlet 2A of the second heat exchanger, and thereby ensuring sufficient heat exchange and stable temperature output of the third heat exchanger 3.

[0051] In one of the embodiments, a low temperature pump back gas pipe is connected to the third inlet 1E of the first heat exchanger, and the third outlet 1F of the first heat exchanger is connected to the inlet of the first compressor 8.

[0052] Specific operation process is as follows: the back gas of the low temperature pump under the 4.5K and 80K regeneration working condition enters into the first heat exchanger 1 through the third regulating valve V3, and after heat exchange to room temperature, enters into the first compressor 8 through the third outlet 1F of the first heat exchanger, the heat exchange process can leave more cold energy in the first heat exchanger 1, thereby reducing the outlet temperature of the second outlet 1D of the first heat exchanger, and reducing the liquid nitrogen consumption of the second heat exchanger 2 and the third heat exchanger 3.

[0053] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present application, and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0054] The part of the present application specification not described in detail belongs to the known technology in the art, and the above embodiments are only for the purpose of describing the present application, and are not intended to limit the scope of the present application. The scope of the present application is defined by the appended claims. Any equivalent replacement and modification made without departing from the spirit and principle of the present application shall be included in the scope of the present application.

Claims

1. A helium cryogenic cycle system for a deuterium-tritium fusion device, characterized in that, It includes a first heat exchanger, a second heat exchanger, a third heat exchanger, a fifth heat exchanger, and a first compressor; A high-temperature helium gas pipe is connected to the first inlet of the first heat exchanger; the first outlet of the first heat exchanger is connected to the inlet of the first compressor; the outlet of the first compressor is connected to the inlet of the fifth heat exchanger; the outlet of the fifth heat exchanger is connected to the second inlet of the first heat exchanger; the second outlet of the first heat exchanger is connected to the first inlet of the second heat exchanger; the first outlet of the second heat exchanger is connected to the inlet of the third heat exchanger; and the outlet of the third heat exchanger is connected to a low-temperature helium gas pipe. The third heat exchanger is immersed in a liquid nitrogen bath. The helium cryogenic circulation system for the deuterium-tritium fusion device further includes a liquid nitrogen reliquefaction device, which includes a second compressor, a sixth heat exchanger, a fourth heat exchanger, an expander, and a second gas-liquid separator. The outlet of the liquid nitrogen tank is connected to the inlet of the second compressor, the outlet of the second compressor is connected to the inlet of the sixth heat exchanger, the outlet of the sixth heat exchanger is connected to the second inlet of the fourth heat exchanger, the second outlet of the fourth heat exchanger is connected to the inlet of the expander, the outlet of the expander is connected to the inlet of the second gas-liquid separator, and the first outlet of the second gas-liquid separator is connected to the first inlet of the liquid nitrogen tank. The liquid nitrogen reliquefaction device further includes a first gas-liquid separator, the first outlet of the second gas-liquid separator is connected to the second inlet of the second heat exchanger, the second outlet of the second heat exchanger is connected to the inlet of the first gas-liquid separator, and the first outlet of the first gas-liquid separator is connected to the second inlet of the liquid nitrogen tank.

2. The helium cryogenic cycle system for a deuterium-tritium fusion device according to claim 1, characterized in that, The second outlet of the second gas-liquid separator is connected to the first inlet of the fourth heat exchanger, and the first outlet of the fourth heat exchanger is connected to the inlet of the second compressor.

3. The helium cryogenic cycle system for a deuterium-tritium fusion device according to claim 1, characterized in that, The second outlet of the first gas-liquid separator is connected to the inlet of the second compressor.

4. The helium cryogenic cycle system for a deuterium-tritium fusion device according to claim 1, characterized in that, The temperature at the second outlet of the second heat exchanger is always higher than the dew point temperature of nitrogen at its pressure.

5. The helium cryogenic cycle system for a deuterium-tritium fusion device according to claim 1, characterized in that, A fourth regulating valve is installed between the first outlet of the second gas-liquid separator and the second inlet of the second heat exchanger. The amount of liquid nitrogen flowing through the second inlet of the second heat exchanger is controlled by adjusting the fourth regulating valve.

6. The helium cryogenic cycle system for a deuterium-tritium fusion device according to claim 1, characterized in that, The cryogenic pump return pipe is connected to the third inlet of the first heat exchanger, and the third outlet of the first heat exchanger is connected to the inlet of the first compressor.

7. The helium cryogenic cycle system for a deuterium-tritium fusion device according to claim 1, characterized in that, The fifth and sixth heat exchangers are water-cooled heat exchangers.

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