Quench analysis, detection & protection of 5-tesla superconducting solenoid magnet using numerical methods

Superconducting (SC) magnets are used in accelerators, high energy physics, material science studies, modalities such as MRI etc. Bhabha Atomic Research Centre in India is constructing a superconducting solenoid magnet for corrosion and Magneto hydro dynamic studies related to development of Lead Lithium cooled ceramic breeder (LLCB). The complete electro-magnet will be maintained at 4.2 K. A sudden irrevocable transition to normal state of SC magnet's operating point is known as quench. During normal operation, the magnet will be storing 2.6 MJ of energy which needs to be dissipated rapidly in the form of heat energy at the time of quench. A quench though not wished to occur is part of normal operation of magnet and has to be explicitly considered while magnet designing for the safety. Uncontrolled quench is catastrophic in nature which may even lead to melt down of windings, punching holes through insulation etc. The possible reasons for quench are lack of stability (design mistakes), transients, conductor movement, resin cracking etc. A quench protection program is written in COMSOL MULTIPHYSICS along with non-linear resistivity module implemented in PYTHON which attempts to estimate the quench parameters for 5 Tesla SC Magnet. This paper discusses the intrinsic quench behavior along with quench parameters (thermal stability limit of SC magnet in terms of MQE, quench propagation velocity, layer voltages) of the SC magnet.