Speaker
Description
SupraFusion is a French research program aiming to boost HTS (High-Temperature Superconductors) technologies towards large-scale societal applications and particularly compact fusion machines. In the framework of this program, a large-scale demonstrator magnet will be designed, manufactured and tested. This ambitious goal requires incremental steps, including the fabrication of smaller prototypes and the development of key technological components.
Ensuring a safe and robust quench protection remains one of the main technological challenges of large-scale HTS magnets. Indeed, the protection of HTS conductors in the event of a quench poses a significant risk of damage due to their inherently slow normal zone propagation velocities (NZPV), particularly for insulated designs. To address this, a first prototype called D0 was developed by CEA to experimentally study quench detection and protection (including NZPV measurements) of a copper stabilized HTS conductor capable of carrying a 10 kA current under a 9 T external field at 4.5 K.
Analytical and numerical studies were conducted to optimize the conductor design. Parametric evaluations identified the optimal copper cross-section, achieving a balance between effective protection and reliable detection. Although the chosen design should ensure safe protection, maintaining temperatures below 100 K for a detection threshold of 100 mV, further improvements were sought. As a result, a second alternative strategy involving the integration of Superconducting Quench Detectors (SQDs) was proposed. This approach aims to enhance detection sensitivity and, consequently, improve the overall safety and reliability of the protection system. This SQD strategy efficiency has been studied numerically and will be shortly tested and qualified experimentally.
