The long-term safety of a repository is achieved with the help of a multiple-barrier concept. The barrier system isolates the radioactive waste from the environment for thousand of years. During this period of time, the radioactivity will be reduced to such an extent that no more radiation can escape from the stored waste.

Scientific calculations of a possible dispersion scenario showed that no contamination of the biosphere will take place in the period up to around 10,000 years after the emplacement of the waste. Radionuclides with a low retention factor in rock, e. g. iodine-129, spread very slowly with the flow velocity of the groundwater and re-enter the biosphere after a period of more than 300,000 years. At that point in time, the possible radiation exposure lies within the range of fluctuation of natural radiation.

All imaginable accidents that could happen during the operation were taken into account (accidents during the individual transport and handling steps of the storage process and the related radiological consequences for the operators and the local population).

The result of the accident analysis was that the design of the repository prevents damage to the machinery and storage containers. Even in the case of a possible discharge of radioactivity, the safety limits of the Radiation Protection Ordinance would not be exceeded.

Radioactive waste is safely isolated from the environment.