RBI and assessment of component life for high temperature service

Risk-based inspection (RBI) can offer justified priorities in timing and targeting of in-service inspections and maintenance action for power and process plants. For this purpose, recommended procedures and tools are increasingly supported by the evolving standardization on risk based assessments and RBI. Successful RBI generally requires availability of background data on design, fabrication, operation and maintenance history, evaluation of the current condition and its expected deterioration in systems and components of interest, and expertise of the RBI team to conduct the assessments. This paper aims to show some RBI related observations, modelling and experiences when considering the accumulating damage, life-limiting mechanisms and failures in high temperature components of thermal power plants. An example is shown from a pilot scale application of RBI on a steam system of a combined heat and power (CHP) plant after more than 200 000 h of service. The implications and experiences are discussed in terms of the implemented inspection and maintenance actions, and perceived benefits of RBI