Importance measures in ranking piping components for risk informed in-service inspection

Risk informed in-service inspection aims at prioritising the components for inspection within the permissible risk level thereby avoiding unnecessary inspections. Various methods have been evolved for prioritisation, in which the importance measure approach has gained a wide popularity. This paper presents an importance measure that can be employed to prioritise components of any dimension, which is normally required from the point of view of carrying out a risk informed in-service inspection of nuclear power plants.