6.23. It should be ensured that the safety case and supporting assessment are based on an appropriate level of understanding of the disposal system and its potential behavior, and that all safety relevant issues are considered and addressed. However, under Principle 5 of Ref. [1], it is stated that the resources devoted to ensuring safety have to be commensurate with the magnitude of the possible radiation risks and their amenability to control. In accordance with this principle, the safety case should be developed and assessment should be conducted only to a level of detail that is appropriate both to the magnitude of the risks and to the stage of development of the disposal facility.