[en] Since a long time, severe accidents are one of the main areas in the surveillance activities of the Swiss Federal Nuclear Safety Inspectorate (ENSI). The analysis of events all over the world and the evaluation of their relevance for the Swiss nuclear power plants belong to the permanent obligations of the regulatory authority. In Switzerland, for more than two decades, core melting accidents are studied using probabilistic safety assessment methods. Comprehensive risk analyses were set up for external events like earthquakes, sabotages or airplane crashes. Strategies for the mitigation of the consequences of severe accidents, so-called Severe Accident Management Guidance (SAMG), were written down by the regulatory authority and made available to the Swiss plant operators. In international comparison the Swiss nuclear power plants have reached a very high standard in the field of severe accidents. Moreover, the safety of the Swiss plants is continuously reviewed by means of permanent supervision and especially through the 10-year periodic safety review. However, the Fukushima accident justifies a renewed evaluation on whether the preparation against severe reactor accidents could be improved and additional measures be taken for the protection of the population. In the present report, ENSI indicates points to be checked, which were considered as important in the course of the analysis of the Fukushima accident, for the future improvement of the nuclear safety and radiation protection in Switzerland. These points were identified from the analysis of the behaviour of the plant staff, techniques and organisation during the accident. The resulting measures concern the plant design, the emergency management, the feed-back from the encountered events, the surveillance, the radiation protection and the safety culture, with a special emphasis on the emergency management in Switzerland. The implementation of the necessary short-term measures was launched by ENSI decrees and is already partly fulfilled. The mean- and long-term measures will be introduced in action plans during the on-going surveillance of the plants. No significant deficiencies were identified in the Swiss power plants. The required improvement of the reliability of the cooling water supply in the nuclear power plant at Muehleberg was already implemented during the 2011 revision of the plant