EAST装置TF馈线新阈值热稳定性分析

Thermal stability analysis of EAST toroidal field feeder under new threshold

EAST(Experimental Advanced Superconducting Tokamak)馈线系统连接超导磁体和高温超导电流引线,为磁体提供馈电通道和失超情况下能量的释放通道,是装置的一个重要部分。近年来,由于纵场(Toroidal Field,TF)馈线系统进口温度升高,出口温度有时超出阈值6.1 K,导致实验终止。为保障EAST实验的继续进行,将TF馈线的出口温度阈值提升至6.5 K。为确定新阈值下超导导体运行安全,通过GANDALF软件对超导导体运行时的温度裕度和稳定性能量裕度进行计算。计算结果表明:在新阈值下,导体的温度裕度大于1.5 K,稳定性裕度大于200 mJ·cm^(-3)。提升阈值后超导导体依旧运行安全。

[Background]The experimental advanced superconducting tokamak(EAST)feeder system is an essential part of the device that connects the superconducting magnet and high-temperature superconducting current lead.It provides the magnet with feeding and energy release channels in the event of quenching.In recent years,owing to the increase in the inlet temperature of the toroidal field(TF)feeder system,the outlet temperature has occasionally exceeded the threshold of 6.1 K,resulting in the termination of the experiment.[Purpose]This study aims to ensure the continuation of the EAST experiment by thermal stability analysis under new TF feeder outlet temperature threshold of 6.5 K.[Methods]Based on the system structure and low-temperature operation data of the TF feeder and superconducting conductor,a mathematical model for temperature margin and current shunt temperature of superconducting conductor was established.Then,the mathematical model and GANDALF software were employed to calculate the temperature and stability margins of superconducting conductors during operation under different background magnetic fields and operating currents.[Results]The calculations results indicate that under the new threshold of 6.5 K,the temperature margin of the conductor is greater than 1.5 K and that the stability energy margin is greater than 200 mJ·cm^(−3).[Conclusions]The superconducting conductor remains safe for use after increasing the threshold.