At the time Switzerland embarked on the peaceful use of nuclear energy, the construction of a deep geological repository for the disposal of radioactive waste was something for the distant future. However, legislators realised that it would be necessary to dispose of waste produced in Switzerland and so in a Federal Decree issued on 6 October 1978 on the Atomic Energy Act they stipulated that permanent and safe disposal of all radioactive wastes must be demonstrated before any general license could be granted for the construction of a new nuclear power plant.
The demonstration of disposal feasibility is a feasibility study designed to show that it would be feasible to provide safe, permanent disposal of radioactive waste in a deep geological repository in Switzerland. The process, however, is not site-specific, i.e. it does not relate to a single site. Rather, it is a statement of principle and must be based on geological data obtained from geological investigations.
In 1985, Nagra submitted a feasibility demonstration for “Oberbauenstock” as a possible site for L/ILW disposal, and in 1988 the Federal Council approved this demonstration of feasibility. At the same time, NAGRA submitted a feasibility demonstration for disposing of HLW in the crystalline bedrocks in the north of Switzerland. However, this was rejected by the Federal Council due to insufficient evidence for the existence of crystalline rocks in Switzerland containing the required quality. Nagra were asked to extend their investigations to include sedimentary rocks. As a result, in 2002 Nagra submitted a feasibility demonstration for a deep geological repository in the Opalinus clay in the Zurich Weinland. The Federal Council approved this demonstration of feasibility on the basis of reports by ENSI and specialist committees and experts. In so doing, the Federal Council was confirming that it was feasible in principle to dispose of all radioactive waste in Switzerland.