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ONR consent for Sizewell B return to service

ONR has granted consent to allow EDF Energy Nuclear Generation Ltd's (EDF NGL), Sizewell B nuclear power station in Suffolk to return to service following its statutory periodic shut down for maintenance, inspection and refuelling.

In coming to this decision, our inspectors have examined the licensee’s arrangements for controlling and completing the maintenance activities, reviewed test and inspection records and inspected plant and equipment. Our interventions did not identify any issues of significance that affect the safety case for the restart of the reactor and its safe operation up to the next planned statutory periodic shutdown in 2017.

During the shutdown a thorough examination (in-service inspection) of the reactor pressure vessel was completed by EDF NGL to confirm the reactor pressure vessel remains in good condition, which it is required to undertake every ten years. ONR's technical specialists examined the results of these in-service inspections and were satisfied that they demonstrate the continued integrity of the reactor pressure vessel and that the hydrogen flaking present in the Doel 3 and Tihange 2 reactors in Belgium is not evident at Sizewell B.

ONR specialists reviewed reports and quality documentation that demonstrate that the Sizewell B reactor pressure vessel domes are not affected by the carbon segregation issue currently the subject of regulatory scrutiny in France for the Flamanville 3 domes.

Areva has confirmed that the reactor components supplied to Sizewell B by its Le Creusot forge facility are not implicated as a result of its recent review of historical records. Its review has highlighted anomalies and omissions in documentation associated with components supplied to other operators in France, and we will continue to monitor the situation, liaising with the French nuclear regulator, ASN.

ONR completed an independent review of the lifetime records held by EdF NGL for the reactor components supplied to Sizewell B by Areva’s Le Creusot forge facility in France and no deficiencies were identified. Combined with the results of the comprehensive in-service inspections from the current and previous outages and third party inspections that were completed during manufacture, this provides us with confidence in the quality and continued safety of the forgings supplied for Sizewell B.

(Cover photo courtesy of EDF Energy Ltd.)

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