The Office for Nuclear Regulation ONR has approved the limit of graphite weight loss at Dungeness B to 8%. This is a small increase from the previous limit of 6.2% and refers to the amount of weight the graphite core is allowed to lose.
Every three years we thoroughly inspect the graphite core as part of our statutory outage.
At Dungeness B, we have used the information from a continuing programme of monitoring, inspection and physical sampling of the graphite core to assess the state of the core. This knowledge feeds in to modelling and analysis which give us the knowledge to allow us to safely increase the limit of weight loss within the core from 6.2% to 8%.
As time goes on we will continue to collect data, build this into our models and calculations and ensure our safety margins are robust and appropriate.
EDF Energy remains focused on achieving a ten-year life extension for Dungeness B which we hope to confirm by the end of the year. To ensure that safety margins continue to be sufficient, we have developed a programme of modifications which will feed in to the plant lifetime extension proposals and enable safe operation to 2028.
Martin Pearson, station director at Dungeness B said: “The increase in weight loss limits has been based on an extensive programme of modelling and sampling. The limits are set at conservative levels and still include wide safety margins. This gives us the knowledge and confidence that the reactors are well within safe limits of operation.”