The CNS confirms: Switzerland complies with international requirements

Convention on Nuclear Safety

The eighth and ninth review conference of the Convention on Nuclear Safety praised Switzerland for the federal partial funding of ENSI’s research programme. The long-term retention of competence for nuclear safety in Switzerland was also highlighted as a challenge. In summary, Switzerland performed well in an international comparison.

The eighth and ninth review conference of the Convention on Nuclear Safety (CNS) of the International Atomic Energy Agency IAEA took place in Vienna from 20 to 31 March. As the eighth conference in 2020 had to be cancelled due to the Covid 19 pandemic, two country reports were assessed at this year’s conference. This year’s review conference was attended by 900 delegates from 81 contracting parties. The parties reported on compliance with the CNS and the principles of the Vienna Declaration.

Passing the last two weeks in review, ENSI Director Marc Kenzelmann said: “The international regulatory exchange of experience enables us to make a constructive assessment of our own oversight function. The three-year cycle of the CNS with reporting, participation and subsequent implementation of the proposed improvement measures is ideal for this purpose. My thanks go out to all ENSI employees who engage in nuclear safety in Switzerland on a day-to-day basis and who made sure that the National Reports were viewed positively.”

The representatives of the contracting countries who assessed the safety of the nuclear facilities in Switzerland in the peer review process praised the open and technically detailed reporting. Switzerland thus meets the requirements of the international convention on nuclear safety.

In the process, Switzerland received a Good Practice.

Good Practice

“Good practice 1: The allocation of a dedicated annual budget from the Swiss government to ENSI, with the necessary legal framework, to specifically provide for conducting research and participating in research projects in support of regulatory activities.”

In addition, three Areas of Good Performance were highlighted:

Areas of Good Performance

“Area of Good Performance 1: Projects and modifications are subject to a four-step procedure, consisting of the concept, the detailed design, installation and commissioning of the systems. This means that safety submissions need to be submitted and approved prior to implementation to ensure they are appropriate and compliant with safety requirements.”

“Area of Good Performance 2: ENSI’s comprehensive regulatory framework on ageing management, including non-accessible plant areas, incorporating the requirements of the revised IAEA Safety Guide SSG-48 and its co-operation with the IAEA and ENSREG.”

“Area of Good Performance 3: The ENSI “Oversight Safety Culture” project (initiated in 2012 and updated after the 2021 IRRS mission) with the aim to assess the safety culture inside ENSI, to identify shortcomings and to define corrective actions.”

A challenge was set to Switzerland:


“Challenge 1: A shortage of qualified staff (for operators, sub-contractors and nuclear safety regulators) which, due to the ban on nuclear new build and the increased demand from decommissioning activities, is a serious challenge to maintaining competence in the medium to long-term.”

The so-called “Country Review Report” contains a detailed summary of the Swiss review process.

Challenges for the international community were identified from the review conference. Among others, the impact of climate change on the safe operation of nuclear facilities, the ageing management and long-term operation of nuclear facilities, as well as the strengthening of international cooperation with regard to emergency preparedness, which are reflected in the so-called Summary Report.

The CNS was also marked by disputes over the war in Ukraine and the safety of the nuclear power plants there. Ukraine reported on the difficulties of complying with the CNS due to the Russian occupation of Ukrainian nuclear facilities.

The concerns of Switzerland and many contracting parties about safety in Ukrainian nuclear facilities due to the Russian invasion were additionally expressed in a Joint Statement.

The tenth review conference of the CNS will take place in April 2026.