Quintessa is providing support to British Energy in a number of key areas associated with the development of defects in the graphite bricks as they age, and predictions of the evolution of graphite properties with time. Advanced statistical methods have been used to enable the safe period of reactor operation to be calculated on the basis of the history of brick defects observed to date, and to determine the optimum future monitoring strategy. These methods will be applied to each of the reactors when they are shutdown for inspection.