The PEGASOS study (Probabilistic Seismic Hazard Analysis for Swiss Nuclear Power Plant Sites) was initiated in 1999 by the Swiss Federal Nuclear Safety Inspectorate (HSK, now ENSI) in order to incorporate scientific advances into engineering practice – a process that is still ongoing after the formal completion of the original project. The PEGASOS Refinement Project was initiated in 2008. An overview of the progress of the work is given by the chronology of the reassessment of the seismic hazard of the Swiss nuclear power plant sites.
Ensuring safety is an ongoing task. The understanding obtained from the PEGASOS and follow-up refinement projects does not represent the indisputable truth, but serves to improve the quality of the hazard analyses step by step. New information and seismic data will continue to be available to the power plant operators and will contribute to updating the seismic hazard analysis in the future.
Switzerland has broken new ground in Europe with the PEGASOS project. The project and its subsequent refinement mean that the seismic hazard of the Swiss power plant sites has been determined according to the state-of-the-art knowledge and the newest data, with the ever-present uncertainties being considered conservatively.
The final report in English can be downloaded here.
- Why has the seismic hazard been reassessed?
- How was the PEGASOS project carried out?
- Why are guidelines needed for the seismic hazard analysis?
- Why were the results of PEGASOS not directly implemented?
- Why is PEGASOS being refined?
- Why was there an interim assessment of the seismic hazard in 2011?
- Where can I find the results of the PEGASOS study?
- Have the PEGASOS results lost weight in the meantime?
- Who are the experts? Were the same experts used in the PEGASOS and PRP projects?
- Who is the contracting organisation for the studies?
- What is the role of ENSI in PEGASOS and the PRP?
- What are the milestones?