Worst case beam incident causes and protection

The failure events which can occur with the fastest timescales in the LHC are mainly associated with the injection and extraction processes. The possible worst-case failure events are catalogued and the protection layers in place to prevent the failure or mitigate the consequences are described. Particular attention is paid to the beam dump system kickers, the energy tracking system, the injection kickers and the aperture/tune kickers. The requirements for the positioning of the dedicated absorbers with respect to the aperture will be recalled, and the implications for the setting-up and operational stability critically examined.