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.

News

22 August 2018

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 being kept under wraps.

8 March 2018

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. “

8 March 2018

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.

6 March 2018

“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. The IRP has been following Axpo’s safety […]

6 March 2018

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 it was safe. The Swiss Federal Nuclear Safety Inspectorate ENSI accepts this proof in 2018.

17 November 2017

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.

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Background Articles

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”.

2 August 2016

A focus on upgrading

ENSI does not only grant approvals in the case of upgrading. Modifications to constructions, parts of installations, systems, equipment and documents that are classified as relevant for safety or technical security have to be approved by law – even in the case of decommissioning.

9 March 2012

New Nuclear Power Plants

In 2008, general licence applications were submitted for three new nuclear power plants in Switzerland: the Mühleberg replacement nuclear power plant, the Beznau 1 & 2 replacement nuclear power plants, and a new construction project at Niederamt in the canton of Solothurn. For the purposes of the general licences, ENSI began by examining whether the […]

More Background Articles

Documents

2017 Research and Experience Report – ENSI-AN-10294

ENSI Review of the Axpo Power AG Safety Case for the Reactor Pressure Vessel of the Beznau NPP Unit 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 […]

Assessment of the Safety Case for the Reactor Pressure Vessel of the Beznau Unit 1 Nuclear Power Plant

The IRP considers that the Axpo Safety Case is acceptable. This is based on the following: It has been established beyond all reasonable doubt that the flaws are laminar ‘agglomerates’ of alumina inclusions, formed during manufacture of the affected RPV shells, and which neither formed nor grew during service. It has been adequately demonstrated that […]

Swiss National Assessment Report for the Topical Peer Review: Ageing Management in Nuclear Power Plants

Topical Peer Review 2017: Ageing Management at the Mühleberg Nuclear Power Plant

Topical Peer Review 2017: Ageing Management at the Leibstadt Nuclear Power Plant

Topical Peer Review 2017: Ageing Management at the Beznau Nuclear Power Plant

Topical Peer Review 2017: Ageing Management at the Gösgen Nuclear Power Plant

2016 ENSI Oversight Report – ENSI-AN-10014

2016 Research and Experience Report – ENSI-AN-9961

2015 ENSI Oversight Report – ENSI-AN-9671

2015 Research and Experience Report – ENSI-AN-9601

This Research and Experience Report describes and rates the findings of the regulatory research into safety, specific instructive events from nuclear facilities abroad, news regarding the international cooperation as well as current changes and developments in underlying surveillance principles in 2015.