Switzerland’s Federal Nuclear Safety Inspectorate (Ensi) has asked the operators of the Gösgen and Beznau NPPs to provide construction and manufacturing documents for steam generator components. Ensi said in a statement it had taken the preventive action following revelations in France that some steam generator components for pressurised water reactor units manufactured at Areva’s Le Creusot forge facility in France and at the Japan Casting and Forging Corporation could be affected by an abnormality in the carbon concentration of steel. “Thus far we have no evidence to indicate that the steam generators at Gösgen and Beznau are affected by impermissible deviations in the material properties,” said Ensi deputy director Georg Schwarz. The issue first came to light in April 2015 when France’s nuclear regulator, the Autorité de Sûreté Nucléaire (ASN), confirmed an anomaly in the composition of steel in some areas of the lid and the bottom of the reactor pressure vessel at the Flamanville-3 EPR under construction in northern France. ASN said this could affect the mechanical properties of the steel and jeopardise the safety of reactors. Switzerland’s other reactor units, at the Mühleberg and Leibstadt NPPS, are boiling water reactors and are not affected.
