Implications of new safety requirements for existing plants

A brief history of Italian experience, with its three nuclear power plants (NPPs) in operation for almost two decades and the newly licensed Caorso NPP, is outlined. The ENEA-DISP approach to backfitting on operating NPPs is described in some detail, including what is considered the correct method of a 'balanced' fulfilment of the new safety requirements. The particular aspect of seismic problems, specific to a country like Italy, and the way in which it is considered to be related to the old NPPs, is examined, in comparison with the general attitude taken for new plants on the entire national territory. The conclusions of such studies, where possible, are given, including the particular case of the Garigliano NPP. The periodic safety reassessment for the old NPPs is under way and its 'status' is briefly described. Finally, the limits and conditions for which risk analysis techniques may be used to further a balanced implementation of new regulations, are discussed. (author)