Parametric Analysis and Optimization of an Integrated Quench Protection System for the GIGA Stellarator Fusion Reactor

This thesis investigates the quench protection system for the GIGA stellarator, a proposed gigawatt-scale fusion reactor. Protecting its high-energy superconducting magnets from a quench using traditional external dump resistors would generate prohibitively high voltages, severely stressing the electrical insulation. To resolve this, the study evaluates an innovative "internal discharge" concept where the coil's structural stainless-steel plates act as a distributed internal resistor. Upon quench detection, current is diverted into these plates, dissipating magnetic energy internally as Joule heating and safely limiting terminal-to-ground voltages to under 500 V. A 1D electro-thermal and hydraulic numerical model was developed using the THEA framework to compare two candidate conductor technologies: Low-Temperature (LTS, Nb3Sn) and High-Temperature Superconductors (HTS, REBCO). The analysis reveals fundamentally different transient behaviors. LTS conductors exhibit rapid quench propagation suitable for standard voltage-based detection, but suffer higher hot-spot temperatures as significant energy remains trapped in the winding. Conversely, HTS conductors show extremely slow propagation, requiring novel temperature-based detection. However, they successfully force almost all magnetic energy into the structural plates, safely containing the hot-spot. The results quantitatively validate the internal dump architecture as a feasible and highly tuneable protection strategy for utility-scale fusion magnets.