SST-1 Toroidal Field Magnet Tests: Some Results and Lessons Learnt

Testing each of the SST-1 Toroidal Field (TF) Magnets under representative conditions in cold with nominal currents was one of the primary and mandatory requisite in the refurbishment of the Steady-State Superconducting Tokamak (SST-1). Under this mandate prior to the SST-1 machine shell re-assembly, each of the 16 SST-1 TF magnets have been tested fully and successfully in a dedicated test stand. The campaign began on June 10, 2010 and was concluded on Jan 24, 2011 spanning over seven and half months without any interruption in-between. These campaigns ensured that all the sixteen TF magnets could be charged to their nominal currents of 10000 A in either two-phase or supercritical cooling conditions with leak-tight inter-double pancake resistances being in the range of 150 pico-ohms to 1200 pico-ohms. Sensors and diagnostics signal conditioning and data acquisitions, magnet quench detection and magnet protection aspects in these campaigns have been precise, extensive and redundant wherever feasible. Test team had many failures as well as several learning in the course of these challenging tasks. Magnet preparations for the tests, the test designs and their executions, some exciting and confidence building experimental results as well as some failure experiences have been presented in this paper.