[en] Starting from the lump-sum criterion of distance, the criterion of MCA has developed based on the idea of limiting accident consequences with the object in mind of guaranteeing the protection of the population in case of the maximum credible accident in its absolute sense. This claim has proved to be indefensible for the utilization and design of the MCA criterion on nuclear power plants of larger capacities on sites near to conurbation centres. Within the concept of design basis accidents this is not claimed, an imperative formulation was found instead concerning the sort of accident to be considered, including possible demands on its safety design. Using probability methods has lead to a blurring of the relationship with the technological system of nuclear power plants for formulating a criterion for the advantage of risk quantification. If the probability method is to be applied in the licensing procedure concerning nuclear power plants it will be one of the tasks of future safety research to elaborate this relationship clearly. (orig.)