WG_3.3 - Reliability

John Stevens

This standard sets forth the minimum, acceptable requirements for the performance of reliability analyses for safety systems when used to address the reliability considerations discussed in industry standards and guidelines. The methods of this standard may also be applied to other systems, including the interactions, if any, between safety and non-safety systems. The requirements should be applied during the phases of design, fabrication, testing, maintenance, and repair of systems and components in nuclear power generating stations and other nuclear facilities. The timing of the analysis depends upon the purpose for which the analysis is performed. This standard applies to the facility owner and other organizations responsible for the activities previously stated.

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 system?s lifetime. They may also be applied during the preoperational phase or at any time during the normal lifetime of a system.

Guidelines for the definition of a reliability program at nuclear power generating stations are developed. Reliability programs during the operating phase of such stations are emphasized; however, the general approach applies to all phases of the nuclear power generating station life cycle (e.g., design, construction, start-up, operating, and decommissioning).

This standard sets forth minimum acceptable requisites for the performance of reliability analyses for safety-related systems of nuclear facilities when used to address the reliability requirements identified in regulations and other standards. The requirement that a reliability analysis be performed does not originate with this standard. However, when reliability analysis is used to demonstrate compliance with reliability requirements, this standard describes an acceptable response to the requirements.

The minimum acceptable requirements for the performance of reliability analyses for safety systems when used to address the reliability considerations discussed in industry standards and guidelines are set forth in this standard. The requirement that a reliability analysis be performed does not originate with this standard. However, when reliability analysis is used to demonstrate compliance with reliability requirements, this standard describes an acceptable response to the requirements.

General reliability and availability analysis methods that can be applied to structures, systems, and components (SSCs) in nuclear power generating stations and other nuclear facilities are contained in this guide.