Structure Design and Optimization of Helium Cooling Tube for Nuclear Fusion Poloidal Coil

doi:10.12096/j.2096-4528.pgt.24123

Abstract

Abstract:

Objectives The helium cooling tube is the core component of the fusion superconducting magnet system. It connects the superconducting magnet cooling channel and the cryogenic system, and is directly related to the operation stability of the superconducting magnet system. Since helium cooling pipes need to be welded on site, the structural design of helium pipes needs to be comprehensively considered from multiple aspects such as functional realization and on-site process operability, and reasonable solutions need to be proposed. Methods Through comprehensive analysis of the polar field structure of the fusion reactor, the structural optimization and pressure loss assessment of the cryogenic helium cooling tube were carried out. A comprehensive comparative analysis of the helium hole size and the optimal design of weld chamfer was carried out from the perspective of structural mechanics. The general requirements for the design criteria of the fusion reactor magnet helium cooling tube were proposed. Based on the structural mechanical analysis and pressure loss analysis of helium cooling tubes, and the comprehensive consideration of field operability, a helium cooling tube design scheme was proposed to meet the requirements of helium cooling tubes for fusion reactor magnets. Results Although short running helium cooling pipes will cause an increase in local pressure loss, which is equivalent to a conductor of 2.7 meters long, the pressure loss caused by them is basically negligible compared with the total length of the coil. Conclusions The adoption of the short track helium tube design scheme can not only meet the functional requirements, but also greatly improve the operability of the field process and meet the requirements of helium cooling tubes for superconducting magnets in fusion reactors.

Key words: thermonuclear fusion, fusion device, poloidal field coil, helium cooling tube, structural design, superconducting magnet, strong magnetic field, plasma

CLC Number:

TK 01

Chunlong ZOU, Shuangsong DU, Feng JIANG, Kun LU, Jing WEI, Guang SHEN, Peter Readman. Structure Design and Optimization of Helium Cooling Tube for Nuclear Fusion Poloidal Coil[J]. Power Generation Technology, 2024, 45(6): 1060-1066.

Figures/Tables 8

Fig. 1 Structural design diagram of helium cooling tube

Fig. 2 Load and boundary constraints for short runway helium cooling pipes

Fig. 3 Definition of helium holes and weld chamfers

Fig. 4 Stress distribution curves of helium inlet tube weld zone and helium hole inner zone under different R

Tab. 1 Type of hole size for helium cooling tubes

尺寸类型	A/mm	B/mm	B/A
1	6	10.0	1.666 67
2	8	13.3	1.666 67
3	10	16.7	1.666 67
4	8	12.0	1.5
5	8	14.4	1.8
6	8	8.0	1.0

Tab. 2 Analysis of stress in the weld and helium hole zones affected by different type of helium hole

尺寸类型	氦进管焊缝区应力/MPa	氦孔内侧应力/MPa	焊缝区应力集中系数	氦孔内侧应力集中系数
1	529	517	1.95	1.91
2	478	521	1.76	1.92
3	470	538	1.73	1.99
4	469	542	1.73	2.00
5	482	511	1.78	1.89
6	454	652	1.68	2.41

Fig. 5 Equivalent flow coefficient diagram

Fig. 6 Relationship between nitrogen flow and pressure loss

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