Journal of the Korean Physical Society

pISSN 0374-4884 eISSN 1976-8524


J. Korean Phy. Soc. 2006; 49(9(6)): 292

Published online December 20, 2006

Copyright © The Korean Physical Society.

Performance Evaluation of Metallic Seal for KSTAR Vacuum Vessel

G. H. Kim, J. S. Bak and Y. S. Lee


The KSTAR vacuum vessel, the enclosed volume of which is about 110 m$^{3}$, has a total of 72 ports that must be equipped with demountable seals, The vacuum vessel is designed for bake-out up to 130${^circ}$ by using pressurized hot water and for a base pressure of 1.33 $ imes $ 10$^{-6}$ Pa. The leak rate for each seal must be less than 1 $ imes $ 10$^{-11}$ Pa $cdot $ m$^{3}$/s and the seal must be compatible with vacuum vessel base pressure of 1.33 $ imes $ 10$^{-6}$ Pa after bake-out. Trypack$^{ extregistered}$ is an energized spring metal seal which consists of an inconel spring and two envelopes surrounding it, and has lower compression load and higher recovery rate. Trypack$^{ extregistered}$ is therefore being widely applied for ultrahigh vacuum, aerospace, semiconductor, and spent nuclear fuel storage applications. In this sealing test, various tests such as compression-decompression cycles, stress relaxation, and a thermal cycle test have been carried out to assess the applicability of Trypack$^{ extregistered}$ for the large and non-circular ports in the KSTAR.