Flow and Thermo-mechanical Analysis of the LHC Sector Helium Relief System

A simultaneous resistive transition of a LHC magnet sector, which may occasionally occur, will cause rapid helium outflow from magnet cryostats to a special relief system composed of long pipes, buffer volumes and accessories. The paper presents some safety and operational aspects of this system. The results show helium dynamic property distributions along the pipes as well as FEM calculations of thermo-structural stresses in the pipe walls.