3.4. Safety after closure is achieved by developing a disposal system in which the various components work together to provide and to ensure the required level of safety. This approach offers flexibility to the designer of a disposal facility to adapt the facility’s layout and engineered barriers so as to take advantage of the natural characteristics of the site and the barrier potential of the host geology, if applicable. Assurance of confidence in safety is also necessary and this may require the consideration of a number of complex issues, including the potential impact of operations on the performance of the disposal facility after closure.