This Safety Guide addresses the necessary technical features of a Level 2 PSA for nuclear power plants in relation to its application@ with emphasis on procedural steps and the essential elements of the PSA rather than on details of the modelling methods@ since modelling is considered to be well documented in the relevant literature. This Safety Guide includes all the steps in the Level 2 PSA process up to@ and including@ the determination of the detailed source terms that would be required as input into a Level 3 PSA.