6.6. The safety case should explain how it is intended that the characteristics and properties of each component of the disposal system will meet their allocated safety functions and how this will evolve with time. This explanation should be supported by the following:@@- An overview of the technical feasibility of the proposed design options, identifying aspects that rely on already proven techniques and those that are new and need future confirmation through experimental tests;@@- An overview of the level of knowledge about the ability of each component of the disposal system to fulfil its expected role under anticipated conditions and disturbing events that have been identified as possible perturbations;@@- An assessment of how the components of the disposal system will function together in a complementary manner to ensure that there is adequate defence in depth and that safety is not unduly dependent on a single safety function.@@These factors should be supplemented by an overview of the planned site characterization programme and the research and development programme to show how missing information will be obtained in the future.