Recent progress and development of Cryogenics system towards refurbishment of SST-1

Under the SST-1 mission mandate, several cryogenics sub-systems have been enhanced and updated for cool-down of SST-1. Upgradation and new developments followed by stringent test procedures have increased the reliability of operation. After preventive maintenance of the helium plant, the facility has been extensively used for the TF/PF coils campaign in excess of 25 cycles. The tests have been carried out with and without using cold circulator in supercritical helium mode. New developments include, 80 K thermal shields along with its booster system, in-house development of vapor cooled current leads rated at 10 kA and their current feeders system, enhanced capacity of Helium recovery system, pneumatic services and 12 kA/16 V DC Switch Mode Power Supply system. Other significant test programs include Octant cold test at 80 K, electrical isolators test for helium and nitrogen and testing of current leads. The above aspects will be briefly discussed in this paper.