Ageing surveillance programmes in Swiss nuclear power plants

Ageing surveillance programmes for Swiss nuclear power plants were started about ten years ago. The following contribution gives an overview of these programmes. They deal with ageing phenomena of materials of mechanical and electrical components, as well as civil structures. For each safety relevant component, the known ageing mechanisms are identified, and the maintenance, testing, inspection and monitoring programmes are then examined with respect to their suitability for detecting the ageing degradation. Programmes and procedures may be adjusted, or new ones introduced to ensure state of science and technology ageing surveillance. Documentation of the plant-specific ageing surveillance programmes is prepared by the nuclear power plant operators and given to the Swiss Federal Nuclear Safety Inspectorate for assessment. Experience with the ageing surveillance programmes over the last ten years shows favourable results for the monitoring of ageing and safe operation of the plants.