Engineering Problems During Completion of the General Electric Coil for the Large Coil Program

摘要

The engineering effort to support coil completion involved the same kinds of analyses one must make to design such a coil from scratch. Detailed finite element analyses located areas of possible structural failure of the coil case or fracture of the seal welds around the bolted flange joints. Areas of extremely high stresses were found and structural fixes were developed and installed to prevent such mechanical failures. Ultrasonic bolt elongation measurements were used for accurately tensioning the flange bolts to achieve the required clamping forces. Considering the large amount of welding required for case reinforcement and the size of these welds (up to 5 cm), special welding procedures were developed and experimentally qualified for 4 K service. Many current-carrying components in the service stack were tightly restrained to avoid damage due to Lorentz forces, yet were allowed to move during both cool-down and movement of the coil pack. Performing these tasks on a partially completed coil within a highly accelerated time frame and with limited resources was a challenge. (ERA citation 12:002940)