This Safety Guide addresses the necessary technical features of a Level 1 PSA and applications for nuclear power plants@ on the basis of internationally recognized good practices. The scope of a Level 1 PSA addressed in this Safety Guide includes all operational conditions of the plant (i.e. full power@ low power and shutdown) and all potential initiating events and potential hazards@ namely: (a) internal initiating events caused by random component failures and human error@ (b) internal hazards (e.g. internal fires and floods@ turbine missiles) and (c) external hazards@ both natural (e.g. earthquake@ high winds@ external floods) and of human-induced (e.g. airplane crash@ accidents at nearby industrial facilities).