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.

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.

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.

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 200mJ·cm^-3.

The superconducting conductor remains safe for use after increasing the threshold.