|WNN reports that James Fisher Nuclear in collaboration with EDF Energy, Serco (now Amec), Bloodworth Consulting and the University of Manchester, developed eddy-current inspection tools designed to assess the condition of graphite within vacated fuel channels in AGRs, and can be used to measure the electrical conductivity and the inferred graphite density.|
AGRs feature a graphite moderator and are cooled using carbon dioxide. The graphite blocks cannot be replaced or repaired during the operating period of the reactors. However, radiation exposure changes the shape and size of the crystallites that comprise graphite, a process known as dimensional change, which in turn degrades the mechanical properties of the graphite.
Graphite ageing is one area used to determine the lifespan of an AGR nuclear power station. Greater understanding of the ageing process by sampling and modelling can lead to them operating longer, giving the UK secure and reliable low-carbon electricity.