[en] After a recall of the regulatory context and references, this guide addresses the strategy for an immediate dismantling of an installation, the dismantling planning, the different phases of the end of life of nuclear base installations, the authorization of definitive stop and dismantling, the preliminary phase preparing the definitive stop (regulatory context, technical aspects), the dismantling phase (regulatory context, technical aspects for the concerned operations, the security functions, hardware important for security, taking ageing into account), and the final status of installations (downgrading, constraints)