Swiss federal authorities

Nuclear Facilities

Switzerland has the following nuclear power plants: Beznau (units 1 and 2), Gösgen and Leibstadt. Also in operation is a research reactor at the Federal Institute of Technology in Lausanne (EPFL). The Central Interim Storage Facility for radioactive waste (Zwilag) and the Federal Government’s Interim Storage Facility in Würenlingen are also monitored by ENSI.

The no longer operational Mühleberg Nuclear Power Plant is being decommissioned. Three research reactors at the Paul Scherrer Institute PSI in Würenlingen have nearly been fully dismantled.

  • NPP Beznau
    Beznau NPP comprises two largely identical two-loop pressurised water reactor units, which began commercial operation in 1969 and 1972 respectively. The net electrical output per unit is 365 MW.
  • NPP Gösgen
    Gösgen NPP is a three-loop pressurised water reactor system. It began commercial operation in 1979. The net electrical output is 1010 MW.
  • NPP Leibstadt
    Leibstadt NPP is a boiling water reactor that began commercial operation in 1984. The net electrical output is 1233 MW.
  • Former Mühleberg Nuclear Power Plant (permanent shutdown)
    Mühleberg NPP, which began commercial operation in 1972 and shut down in 2019, was a boiling water reactor with a net electrical output of 373 MW. Mühleberg NPP ceased power operations on 20 December 2019. In 2020, all fuel elements were transferred from the reactor pressure vessel to the fuel pond and the necessary measures implemented to establish safe technical post-operation. In 2022 and 2023, during decommissioning phase 1, Mühleberg NPP transported all its fuel elements to the Central Interim Storage Facility of Zwilag in Würenlingen, completing the first decommissioning phase in 2023. Since then, Mühleberg NPP has been in decommissioning phase 2.

Decommissioning of the following plants has been completed:

  • Lucens experimental nuclear power plant
  • Basel University Research Reactor
    Up until its final shutdown in 2015, the research reactor of Basel University was used to teach students and for neutron activation analysis. After the Federal Department of the Environment, Transport, Energy and Communications (DETEC) had ordered the decommissioning of the research reactor on 13 February 2019, ENSI approved the dismantling of the plant. Dismantling was completed in 2019. With the removal of the plant from federal government oversight, the first decommissioning project in Switzerland under the current nuclear energy legislation was completed.

News

  • News, Posts

    IAEA Director General receives an insight into Swiss backfitting philosophy

    ENSI experts gave the Head of the International Atomic Energy Agency (IAEA), Rafael Grossi, a guided tour of the Beznau nuclear power plant during a working visit to Switzerland. Grossi was given a picture of the continuous improvements made to nuclear safety as laid down in the Vienna Declaration, in the setting of the Beznau…

  • News, Posts

    ENSI’s assessment of earthquake safety at the Beznau nuclear power plant ruled correctly

    The Swiss Federal Nuclear Safety Inspectorate assessed the earthquake safety of the Beznau nuclear power plant in accordance with the legal requirements. The Swiss Federal Administrative Court has thus rejected an appeal lodged by 15 individuals.

  • News, Posts

    New studies on protection of Swiss nuclear power plants against a deliberate plane crash now completed

    Swiss nuclear power plants have an adequate level of protection against a deliberate plane crash. This is confirmed by an update of the associated analyses ordered by the Swiss Federal Nuclear Safety Inspectorate (ENSI) in 2013. For security reasons, the details are confidential.

  • News, Posts

    Video interview: Beznau 1 Nuclear Power Plant gets the go-ahead to start up again

    Hans Wanner, Director General of ENSI: “Axpo has proved that the inclusions found in the steel of the reactor pressure vessel do not have a negative effect on the safety. ”

  • News

    Beznau 1: Aluminium oxide inclusions do not have a negative impact on reactor pressure vessel safety

    Beznau 1 NPP gets the go-ahead to start up again. Axpo has proved that the inclusions found in the steel of the reactor pressure vessel do not have a negative effect on safety. ENSI, the Swiss Federal Nuclear Safety Inspectorate, has reviewed and accepted the safety case.

  • Interviews, News, Posts

    “Extensive test program shows no evidence of a detrimental effect of the inclusions on the brittle fracture reference temperature”

    An international panel of experts supported the Swiss Federal Nuclear Safety Inspectorate ENSI in assessing Axpo’s safety case for the Beznau 1 reactor pressure vessel. In an interview, the chair of the review panel Tim Williams explains why they support the conclusion that Beznau 1 may be restarted.

  • News, Posts

    Chronology: from the findings in Belgium to the proof of safety from Beznau 1

    In the summer of 2012, findings are detected in the basic material of the reactor pressure vessel of the Belgian nuclear power plant Doel-3. As a result, nuclear power plants in Switzerland also have to carry out inspections. Since findings are also detected in the reactor pressure vessel of Beznau 1, Axpo needs to prove…

  • News, Posts

    Quality assurance errors relating to some fuel rods in the Leibstadt Nuclear Power Plant

    A few days ago, Leibstadt Nuclear Power Plant (KKL) informed the Swiss Federal Nuclear Safety Inspectorate (ENSI) that some fuel elements do not fulfil the requirements of the applicable specifications. Accordingly, KKL decided to replace them for safety reasons. The safety of man and the environment was ensured at all times.

  • News, Posts

    The carbon content of the steam generators at Beznau and Gösgen is not too high

    The steam generators at Beznau and Gösgen do not deviate from the design requirements in terms of their carbon content. This is the result of a review of the manufacturing documents. The structural integrity of the steam generators’ individual components is ensured by a large margin.