The term "demonstration of feasibility" refers to the provision of evidence that it is in principle possible to dispose of radioactive waste produced in Switzerland in a specific geological layer. The document is not a licence or a choice of site for a deep geological repository. It merely indicates that a sufficiently large and suitable rock formation exists in which a deep geological repository could be built. The requirement of a demonstration of feasibility of disposal fulfils the need of the federal parliament to ascertain at an early stage that the safe disposal of radioactive waste in Switzerland at a later point in time is assured in principle. The safe disposal of radioactive waste at a specifically designated site must be established independently of the demonstration of feasibility on a step-by-step basis in the licensing procedure in accordance with legislation governing nuclear energy. This procedure takes place within the context of a detailed storage project and on the basis of studies carried out at a specific site.
The demonstration of feasibility of disposal must be furnished by those responsible for the disposal of nuclear waste and has been required by law since 1978. Since then it has been a fundamental requirement for the operation of nuclear facilities in Switzerland. In 1988, the Federal Council approved the demonstration of feasibility of disposal for low and intermediate-level waste after the National Cooperative for the Disposal of Nuclear Waste (Nagra) had supplied the required evidence based on a possible repository in marl host rock beneath the Oberbauenstock (canton of Uri). Then, at the end of 2002, Nagra submitted an application for the demonstration of feasibility of disposal for high-level radioactive waste, which was based on the opalinus clay formation beneath Zurich Weinland. The Federal Council adopted this demonstration of feasibility of disposal in 2006. With these approvals, the Federal Council confirmed that the disposal of radioactive waste in Switzerland is possible in principle.