Quench Analysis and Experiment of CiADS Linac Superconducting Solenoid

The China initiative accelerate driven system (CiADS) is dedicated to the safe disposal of long-lived nuclear waste. It consists of a superconducting linac, a subcritical fast neutron reactor system, a high-power heavy metal spallation target, and other auxiliary devices. To constrain and regulate the beam, three superconducting magnet structures are applied to the linac superconducting portion. They are made up of two solenoids, two horizontal steering dipole coils, two vertical steering dipole coils, and two shielding coils with varying axial lengths. In OPERA-Quench, a three-dimensional quench simulation of the magnet is performed, and the hot-spot temperature and terminal voltage in the quench process are presented. The stored energy of the superconducting magnet increases as the axis length increases, and so does the hot-spot temperature and terminal voltage. The maximum stored energy of the superconducting magnet is 27.19 kJ, corresponding to a hot-spot temperature of 70.9 K and a peak terminal voltage of 422 V, all of which are within safe limits. The experiment is performed with the protection circuit, the hot-spot temperature is calculated from the test data, the current and voltage are also compared to the simulation results, and the difference between simulation and experiment data is evaluated and analyzed. Finally, in order to avoid excessive liquid helium consumption in the cryostat, as much magnet energy is expended on the discharge resistor as feasible. The differences between various dump resistors and varistor are compared. The energy absorbed by the varistor are better than resistors.