Overall behaviour of PFC integrated SST-1 vacuum system

10th Asia Plasma and Fusion Association Conference

Khan, Ziauddin^1 ; Raval, Dilip C.^1 ; Paravasu, Yuvakiran^1 ; Semwal, Pratibha^1 ; Dhanani, Kalpeshkumar R.^1 ; George, Siju^1 ; Shoaib, Mohammad^1 ; Prakash, Arun^1 ; Babu, Gattu R.^1 ; Thankey, Prashant^1 ; Pathan, Firozkhan S.^1 ; Pradhan, Subrata^1

Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar

382 428, India^1

关键词: Gaseous impurities;    Plasma-facing components;    Pumping systems;    Steady state superconducting tokamak (SST-1);    Surface impurities;    Total surface area;    Turbo molecular pumps;    Vacuum chambers;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/823/1/012060/pdf
DOI  :  10.1088/1742-6596/823/1/012060

来源: IOP

【 摘 要 】

As a part of phase-I up-gradation of Steady-state Superconducting Tokamak (SST-1), Graphite Plasma Facing Components (PFCs) have been integrated inside SST-1 vacuum vessel as a first wall (FW) during Nov 14 and May 2015. The SST-1 FW has a total surface area of the installed PFCs exposed to plasma is ∼ 40 m2which is nearly 50% of the total surface area of stainless steel vacuum chamber (∼75 m2). The volume of the vessel within the PFCs is ∼ 16 m3. After the integration of PFCs, the entire vessel as well as the PFC cooling/baking circuits has been qualified with an integrated helium leak tightness of -8mbar 1/s. The pumping system of the SST-1 vacuum vessel comprises of one number of Roots' pump, four numbers of turbomolecular pumps and a cryopump. After the initial pump down, the PFCs were baked at 250 °C for nearly 20 hours employing hot nitrogen gas to remove the absorbed water vapours. Thereafter, Helium glow discharges cleaning were carried out towards the removal of surface impurities. The pump down characteristics of SST-1 vacuum chamber and the changes in the residual gaseous impurities after the installation of the PFCs will be discussed in this paper.