Two Swiss nuclear plants to be checked for irregularities

The Beznau nuclear power plant reactor block 1 in canton Aargau has steam generators which must be checked for possible anomalies Keystone

The Swiss Federal Nuclear Safety Inspectorate (IFSN) has confirmed that steam generators at the Beznau and Gösgen nuclear plants must be checked for possible anomalies.

In a statement on TuesdayExternal link, IFSN said it had asked the operators of the Beznau and Gösgen nuclear plants to check the quality of steel components used in the steam generators.

Plant operators must scrutinize documents relating to the components and report to IFSN by April. They should then carry out any physical checks on materials.

The news follows reports that the French nuclear safety authority (ASN) discovered in June that certain steam generator channel heads made by two different manufacturers – Areva’s Creusot plant and Japan Casting & Forging Corp (JCFC) – could contain a zone comprising a high carbon concentration. That could weaken the mechanical resilience of the steel and its ability to resist the spreading of cracks.

“This pushed us to check the steam generators at the Beznau and Gösgen plants,” said IFSN interim director, Georg Schwarz.

The steam generators at Beznau were replaced in the 1990s. Those currently in service at Beznau were manufactured by Creusot. Those in Gösgen were made in Germany.

IFSN could not confirm to Swiss public radio, RTS, whether the tests to Beznau and Gösgen would lead to temporary closures. In France, a third of the country’s ageing nuclear reactors were closed for safety checks after the country’s regulator ordered a review of the strength of crucial steel components after the discovery of manufacturing irregularities.

Switzerland has five nuclear power reactors, generating about 34.5% of its electricity. It uses nuclear energy to produce electricity, in research and medicine. Two reactors, Beznau 1 and Leibstadt, are currently off grid due to repairs. The Mühleberg plant will be closed down in 2019 according to the power station operators.