As the UK nuclear safety regulator, the Office for Nuclear Regulation would not allow continued operation of any nuclear reactor unless it was safe to do so. We recognise the challenges presented by ageing of the Advanced Gas-cooled Reactor (AGR) fleet in the UK, and we continue to pay close attention to the problems associated with the graphite core of the reactors. We are satisfied that the reactors are safe to operate. It is the responsibility of the operator, EDF to monitor the graphite behaviour and demonstrate the continued safe operation of the reactors to the satisfaction of ONR.
ONR is currently writing a Project Assessment Report (PAR) to support a decision on whether or not to grant a Consent for Dungeness B (DNB) Reactor 21 Return To Service (RTS) after its current periodic shutdown. ONR's regulatory judgement on the acceptability of "graphite weight loss" safety case work will be a part of this PAR, but the PAR will also cover an extensive amount of routine periodic shutdown work. The PAR will go through ONR's due internal review before a decision is taken on whether or not to grant a Consent for RTS on Reactor 21. ONR cannot give a firm date for the completion of this work but provided there are no unexpected delays it is likely that the PAR will be published on the ONR web site by the end of June
Details can be found in the "Non-Routine Matters" sections of ONR's Dungeness B Site Stakeholder Group (SSG) quarterly reports.
The Radioactivity in Food and the Environment (RIFE) report "RIFE - 18" provides relevant information.