The 1040 MW Dungeness B power station (pictured) in Kent, England came online in 1983 and is currently scheduled for decommissioning in 2018. It consists of two advanced gas-cooled reactors.
The plant’s owner, EDF Energy, announced in 2012 that it hopes to extend the power station’s operating life by up to 10 years. A decision will be made by the end of this year, the company said.
That goal may be closer since the national Office for Nuclear Regulation has approved raising the amount of weight the plant’s graphite core can lose to 8 per cent, from its previous safety limit of 6.2 per cent, per EDF’s request.
The graphite bricks in the plant’s core degrade over time due to radiation exposure, losing weight and developing cracks. According to reports, the plant would have breached the 6.2 per cent safety limit this year. EDF applied to have the limit extended when the weight loss stood at 5.7 per cent.
The new safety limit will allow the plant to run until 2020, less than the full 10-year life extension EDF would like to see.
Juliette Sanders, an EDF media officer, said: “EDF Energy remains focused on achieving a 10-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.”
Professor Paul Mummery of Manchester University said in a BBC interview that while the original limits were “conservative”, it may prove uneconomic for EDF to keep the reactors online in the long term as the regulator could require additional safety inspections.