NSTX flag joint fastener design, testing, and fatigue analysis

In February of 2003 NSTX experienced a fault in the TF coil system resulting in damage to the center stack TF bundle. Subsequent investigation revealed that unexpected loading of the TF bus connections had led to failure in the "TF flag" bus area. Design improvements were made with respect to the TF flag support structure and detailed analysis was performed to substantiate the new approach under both static and fatigue loading. Component and prototype testing was used to verify the validity of the analysis. This paper briefly reviews the redesign and details the analysis and testing associated with the TF flag joint hardware.