Abstract
This paper describes the contents of “Guidelines on Reliability Target Establishment and Conformity Evaluation for Passive Components” newly developed by the Japan Society of Mechanical Engineers (JSME). JSME developed the guidelines to provide a methodology that allows for the application of risk-informed and performance-based approaches to nuclear passive components. They are technology-inclusive covering new and existing reactors and applicable to all conduits in a lifecycle of a nuclear plant, i.e., design, fabrication, installation, inspection, operation and maintenance. The methodology consists of four steps: 1) task definition, 2) reliability target establishment for a component of interest, 3) structural reliability assessment of the component, and 4) conformity evaluation of the component to the reliability target (integrated decision making). One of the features of the guidelines is that conformity evaluation is performed in an integrated fashion, i.e., not only by comparing an established reliability target and assessed structural reliability but also by ensuring the validity of assessments, the sufficiency of structural reliability considering associated uncertainties, and the consistency with the design philosophy of nuclear power plants, i.e., defense-in-depth and maintaining margins. The first edition of the guidelines will focus on providing a general framework, while more detailed guidance alongside some worked examples is being elaborated to be implemented into the guidelines at the next revision.
