25 Jul (NucNet): French nuclear regulator Autorité de Sûreté Nucléaire (ASN) has approved the restart of the Bugey-5 pressurised water reactor in eastern France, which has been in cold shutdown since August 2015 due to sealing problems in the reactor containment building.
State-controlled nuclear fleet operator EDF had been unable to find the source of leaks in the containment building’s steel inner lining, but said in March 2017 that it was employing new techniques in a bid to restart the 880-MW unit.
EDF said it would use a “sealing composite” and lime mortar to resolve the sealing problems.
On 24 July 2017, ASN said EDF had carried out the repairs and a new test of the containment had confirmed “a leakage rate in compliance with general operating rules”.
ASN said it had told EDF on 18 July 2017 that the unit could be restarted.
Significant leaks from the containment were first seen during a pressure test carried out in 2011 during the unit’s third decennial inspection.
In December 2014, ASN said new tests of the containment should be carried out during the reactor’s next shutdown.
EDF carried out those tests during a shutdown in August 2015. However, ASN said the tests showed there had been further degradation of the inner liner of the containment.
Leaks were also found in the lower part of the reactor building.
Bugey-5 began commercial operation in January 1980. The Bugey nuclear station has four commercial nuclear units.
