Power plant component condition monitoring with respect of fatigue and creep-fatigue requires information about the real operational loading of the component. Load monitoring systems are available on the market for that purpose. The retrieved load information can be further processed in terms of fatigue assessment based on realistic loading. Moreover, the combination of load monitoring, derivation of stress-time-histories for sentinel locations, cycle counting and fracture mechanics based assessment paves the way of substantiated determination and optimization of non-destructive testing (NDT) inspection intervals. This approach enables a continuous structural health monitoring of critical components even in the sense of online-monitoring capabilities.
This approach provides — in addition to the established fatigue analysis — concrete decisions for the remaining component lifetime and the maximum inspection intervals. This method can also be used if the previous lifetime consumption is unknown. It basically constitutes an advanced damage tolerance approach.
The paper describes a newly developed solution which combines the established Fast Fatigue Evaluation (FFE) approach of Framatome with the THERRI capabilities of TÜV NORD.