Electromechanical Analysis of the Busbar Support System in the LHC Electrical Feed Boxes and Their Consolidation With Remotely Installed Clamps

The Large Hadron Collider (LHC) main superconducting circuits are powered by cryogenic electrical feed boxes located at each end of the eight arc segments of the LHC. Preliminary electromechanical analysis identified poorly supported busbars in the cryostat interfacing with the LHC magnets and supporting the beam pipes. To account for the nonlinear electromechanical behavior of the busbars, a refined iterative method of analysis was developed to accurately predict their displacement and improve the support system design. Inspection of the busbars at the start of the first long shutdown of the LHC confirmed the calculated displacements, and the decision was taken to consolidate the support system by installing clamps on the busbars. To avoid deforming the cryostat and misaligning the beam pipes, clamps were developed for remote installation through the existing busbar ducts. They were validated with a specific test program to ensure their structural, cryogenic, and electrical performance. Sixteen clamps were successfully installed in the eight feed boxes of the LHC using an endoscope and specifically developed tooling.