To a certain extent, the public regard radiation from nuclear facilities as more dangerous than that from natural sources or medicinal applications even though there is no scientific justification for this view. Operators of nuclear facilities endeavour to keep radiation releases at a level much below the limits specified in law. The latter are defined in such a way that the limit set by the Swiss Federal Council in the Radiological Protection Ordinance for public exposure to radiation is not exceeded even if very unfavourable assumptions were to apply.