Revision Standard - Active.The basic principles that are needed to conduct a reliability analysis of safety systems are provided for designers and operators of nuclear power plant safety systems and the concerned regulatory groups. By applying the principles given, systems may be analyzed, results may be compared with reliability objectives, and the basis for decisions may be suitably documented. The quantitative principles are applicable to the analysis of the effects of component failures on safety system reliability. Although they have their greatest value during the design phase, the principles are applicable during any phase of the systems lifetime. They may also be applied during the preoperational phase or at any time during the normal lifetime of a system.