[en] In the first controlled nuclear chain reaction in history - Enrico Fermi's 1942 Chicago Pile experiment - the concept of 'nuclear safety' consisted of three cadmium rods. It is gratifying to note, 61 years later, that our concepts of 'Defence in Depth' - and nuclear safety overall - have evolved considerably. But it is also interesting to observe that the basic elements of the equation remain essentially the same: automatic safety features, emergency back-ups, and the human interface, all coordinated in an effort to manage and minimize the risks associated with harnessing nuclear energy. This statement reviews a number of the key lessons we have learned from the successes and failures of the past six decades