Requests for permission to photocopy portions of this material for public or commercial use shall be addressed directly to the Copyri^rt Clearance Center (CCC) at mfo@copyright.com or the Centre francais Sexploitation du droit de copie (CFC) contact@cfcopies.com. This study, which examines a selection of OECD member countries, validates the often intuitive assumption that, as a largely domestic source of electricity with stable costs and no greenhouse gas emissions during production, nuclear energy is well-placed to make a significant, positive contribution. With the help of a series of transparent and policy-relevant indicators, the study shows in particular that nuclear energy has indeed contributed to improving energy supply security in OECD countries in a significant manner during the past 40 years.