EDF Energy applied to extend the limit on how much degradation can take place to the graphite bricks surrounding the nuclear core at its Kent-based nuclear site, and told Utility Week that the rest of its site are under review as safety margins continue to shrink.
“The figures we have for our sites are well within the safety margins we have been set. But we will keep this under review during the operational lives of our sites, and as is usual work with the Office for Nuclear Regulation,” a spokesman for the company said.
The Heysham 1 nuclear power unit is the reactor closest to reaching its safety standards relating to graphite weight loss, at just 1.5 per cent off its limit. Current average weight loss is at 10.5 per cent with its limit being 12 per cent.
A final decision as to whether the Heysham plant’s lifetime may be extended to 2019 will be made by the regulator next year following detailed safety assessment of the site which will be shared with the Office for Nuclear Regulation.
If the life extension is not approved a safety limit change may be unnecessary as the plant would close in 2016. However, if the plant’s life extension is approved, an application to change the safety limits may be required.
Limits are set as nuclear radiation causes the graphite to lose weight as part of the ageing process and when these limits have been exceeded the power stations is deemed a safety risk.
In a statement EDF Energy’s director of nuclear operations Brian Cowell said: “The safety of the public and our employees is our overriding priority,” adding that extension of the weight loss limit wouldn’t be considered if it posed a threat to surrounding communities.
“EDF Energy takes a cautious approach, works closely with the regulator and operates with very conservative safety margins,” he added.