EDF Energy has applied to extend the ONR limit on how much degradation can take place to the bricks surrounding the nuclear core at its Kent-based nuclear site.
Nuclear radiation causes the graphite bricks to degrade, with the current allowable ‘weight loss’ limit set at 6.2%. EDF Energy would like to see this limit extended to 8%, it said in its application to the regulator.
“The ONR is currently assessing the justification for this increase submitted by EDF, and there is no indication that there are any safety concerns with the increase to this limit,” the ONR said in a statement Wednesday morning.
The regulator said EDF Energy is required to determine the rate of weight loss and cracking to the graphite bricks through “extensive research” which it will need to present to the regulator as part of its application.
“If there is evidence to suggest that the limit of weight loss can be increased, and we are satisfied with the associated justification provided by the operator, we will agree to it,” the ONR added.
EDF Energy was quick to point out that the safety limits themselves are “extremely conservative”, so no real risk is posed to its employees or the local community.
“e’re still miles away from the boundary between safe and not, we’re not operating on that boundary and have extremely conservative limits,” a spokeswoman for EDF told Utility Week.
Dungeness B station director Martin Pearson added that safety assessments change as the company uncovers new information.
“We work continuously with experts and UK universities to understand how materials in our nuclear reactors change over time and how that will affect the stations’ operations. We regularly refine our own safety assessments as we uncover new information,” Pearson said in a statement.
A safety limit change would be required by the 30 year old nuclear plant in order to extend its lifetime to 45 years.
In February this year EDF Energy applied for a ten year life extension for the plant to enable it to operate until at least 2023.