Ageing management in nuclear power plants: Swiss National Assessment Report submitted to the European Commission

The general conditions for systematic ageing management are fulfilled in Switzerland. This enables the timely detection of any age related degradation, and initiation of suitable counter measures. This was the conclusion reached by the Swiss Federal Nuclear Safety Inspectorate (ENSI) within the framework of an international review of ageing management in nuclear power plants. ENSI authored the Swiss National Assessment Report and submitted it at the end of 2017 to the European Nuclear Safety Regulator Group ENSREG. In doing so, ENSI also identified a number of areas for improvement.

Overall, ENSI concluded in its National Assessment Report for the Topical Peer Review that the regulatory framework (guidelines, laws and organisations) exists in a form that is appropriate for ensuring systematic ageing management. The requirements of the International Atomic Energy Agency IAEA and the Western European Nuclear Regulators Association WENRA are implemented in Switzerland.

The annual reporting of the licensees shows that ageing management in the Swiss nuclear power plants is implemented in accordance with the regulations and continuously updated. In the report to ENSREG, ENSI lists further good practices.

Identified potential improvement areas

Irrespective of its positive assessment, ENSI has, within the scope of its review, identified the following potential improvement areas:

  • Further harmonisation of reporting among the Swiss nuclear power plants is necessary. This concerns in particular the overview of the updated fact sheets, the evaluation of international operating experience and the assessment of the effectiveness of the ageing management programme.
  • In future, as part of its regulatory activities, ENSI will increase its ageing monitoring activities and check whether all safety-relevant pipes have been recorded and covered by suitable maintenance and inspection programmes.
  • ENSI has requested the monitoring of inaccessible or difficult to access parts of civil engineering structures. Up until now, such methods have only rarely been implemented. Therefore, there is still no reliable documentation available in respect of inaccessible civil engineering structures. In its future inspections, ENSI will increasingly insist on appropriate tests.

Specifications for ageing management since 1991

Ageing monitoring programmes have been a legal requirements for nuclear power plant licensees in Switzerland since 1991. In 2008, the particular importance of ageing management was also underlined by a related regulation of the Federal Department of the Environment, Transport, Energy and Communications, DETEC. According to this, a nuclear power plant must be temporarily shutdown, if impermissible age related degradation is detected at one of the barriers (reactor pressure vessel, primary system, containment and reactor building).

International review of the National Assessment Report

The review of ageing management in the nuclear power plants takes place within the framework of the ENSREG Topical Peer Review 2017. Under this review, all participating countries first undertake an assessment of their nuclear power plants in respect of ageing management. In a second step, all participating countries and the European Commission conduct a peer review of the respective National Assessment Reports. Finally, each country defines actions resulting from the review.