Upgrading of DC mechanical breaker for quench protection system of superconducting fusion devices

Controlled fusion technology has received a lot of attention due to its ability to produce pollution-free, nearly unlimited energy. Currently, tokamak is the most promising technical solution. To generate a strong magnetic field to confine the plasma, tokamaks commonly use superconducting magnets. In order to prevent superconducting magnets from quenching, the quench protection system should be deployed. Recently, some tokamaks have placed higher demands on the speed of the quench protection system to improve system reliability, and existing equipment has had difficulty meeting those demands. To solve this question, this study upgraded the drive mechanism of the bypass switch from a pneumatic actuator to a bi-stable permanent magnet actuator. The availability was verified by finite element simulation and prototype testing. After upgrading, the opening time of the bypass switch is reduced from 450 ms to less than 150 ms, which greatly enhances the reliability of the quench protection system.