Switzerland has five nuclear power plants: Beznau I & II, Mühleberg, Gösgen and Leibstadt. In addition to the nuclear power plants, three research reactors are in operation: at the Paul Scherrer Institute in Würenlingen, the Swiss Federal Institute of Technology (ETH) in Lausanne and the University of Basel. And finally, the national central interim storage facility for radioactive waste (ZWILAG) and the Federal Government interim storage facility at Würenlingen are also monitored by ENSI.

Background Articles

22 February 2021

New study on extreme flooding of the River Aare is also relevant for nuclear power plant sites

Today, the Federal Office of the Environment, FOEN, published its study “Extreme Flooding of the River Aare”. Their findings also include a re-evaluation of the flood risk to nuclear installations located on the Aare.

5 February 2021

All Swiss nuclear power plants comply with the updated earthquake safety standards

For the second time since the Fukushima accident in 2011, power plant operators have demonstrated that their plants are capable of withstanding an extremely rare, severe earthquake.

5 December 2018

Series of articles on barriers 6/6: The containment holds radioactive substances in the reactor building

The reactor pressure vessel is enclosed by the containment as the third barrier. This consists of a steel primary containment and a concrete secondary containment.

28 November 2018

Series of articles on barriers 5/6: The water circuit (primary circuit part 2 of 2)

With its pipelines, shut-off valves and other components, the cooling circuit, together with the reactor pressure vessel, is the second barrier for trapping radioactive substances

21 November 2018

Series of articles on barriers 4/6: The reactor pressure vessel (primary circuit part 1 of 2)

The reactor pressure vessel, together with the water’s cooling circuit, is the second barrier for trapping radioactive substances.

14 November 2018

Series of articles on barriers 3/6: The fuel rod cladding tubes (fuel assemblies part 2 of 2)

The fuel pellets are filled into metal tubes. Together with the nuclear fuel matrix, the cladding tubes are the first barrier for trapping radioactive substances in nuclear power plants.

7 November 2018

Series of articles on barriers 2/6: The nuclear fuel matrix (fuel assemblies part 1 of 2)

The nuclear fuel is pressed into pellets and compacted using the sintering process before use in nuclear power plants. This process transforms the nuclear fuel into a ceramic material, which is able to retain the fission products that arise during operation in the nuclear fuel matrix.

31 October 2018

Series of articles on barriers 1/6: Barriers protect people and the environment from radioactive substances

The barrier concept aims to trap sources of radiation in nuclear facilities across several levels. Similar to the layers of an onion, independent barriers ensure that the risk from sources of radiation are minimised for people and the environment.

19 December 2016

Dryout: Preventing inadequate cooling of fuel rods

Heat is generated in the reactor as a result of nuclear fission. To guarantee optimum cooling of the fuel rods, their cladding tubes must always be covered with a film of water. If they are not completely covered with water in specific areas, this is referred to as “dryout”.