Reliability of the Quench Protection System for the LHC Superconducting Elements

The huge energy stored in the Large Hadron Collider (LHC) could potentially cause severe damage when the superconducting state disappears (quench) if precautions are not taken. Most of the superconducting elements in this accelerator require protection in case of resistive transition. The reliability of the Quench Protection System will have a very important impact on the overall LHC performance. Existing high energy accelerators were conceived as prototypes whose main objective was not the efficiency but to push the performance to the limit. The LHC will be the first large accelerator with reliability oriented design. This thesis focuses on adapting the reliability theory and methods that are currently used by the industry and small accelerators to the protection systems of larger and more complex machines like the LHC. Two main contributions have been achieved. Firstly, the author has developed an analytical model for a general multi-state protection system, which is able to include the specific characteristics of a large superconducting accelerator. In order to provide a tool for its implementation and related computations, the simulation program RESQP (REliability Software for Quench Protection studies) has been developed. Secondly, a theoretical and experimental analysis of the LHC Quench Protection System dependability has been carried out.