A new graphite irradiation research program has been launched in support of ageing management of Advanced Gas-Cooled Reactors (AGRs) in the UK. Last week, EDF Energy announced new scheduled closure dates for four of its UK AGR nuclear power plants. AGR reactors feature a graphite moderator and are cooled using carbon dioxide. The graphite blocks cannot be replaced or repaired during the operating life of the reactors. However, radiation damage 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. For continued operation, it is therefore necessary to demonstrate that the graphite can still perform its intended role irrespective of the degradation. EDF Energy – together with Atkins, Frazer Nash and NRG – launched the Blackstone project in 2006. The project aims to simulate accelerated aging of reactor graphite. This involves neutron irradiation at the right temperature combined with simultaneous radiolytic oxidation.
World Nuclear News 22nd Feb 2016 read more »