4 Apr (NucNet): French nuclear regulator Autorité de Sûreté Nucléaire (ASN) said on 3 April 2017 that solutions offered by state-controlled utility EDF to resolve sealing issues at its Bugey-5 reactor were appropriate and would remedy faults at the reactor. The 880-MW pressurised water reactor in eastern France has been in cold shutdown since August 2015 due to sealing problems as nuclear fleet operator EDF has been unable to find the source of leaks in the reactor containment building’s steel inner lining. EDF said last month that it was employing new techniques in a bid to restart Bugey-5. ASN said it had authorised EDF to apply the proposed solutions, which the agency will test. It added that the restart of the reactor was subject to its final approval. EDF has said it will use a “sealing composite” and lime mortar to resolve the sealing problems. In November 2016 ASN extended the deadline for checks on Bugey-5. 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. In April 2016 EDF submitted a safety case detailing proposals on how to deal with the issue. At the time ASN said the safety case was “technically complex” and was being reviewed by ASN and its technical support organisation, the Institute for Radiological Protection and Nuclear Safety (IRSN). Those reviews have now been completed. Bugey-5 began commercial operation in January 1980. The Bugey nuclear station has four commercial nuclear units.
