Arab - Niroo, Consulting Engineers
Taheri - Niroo, Consulting Engineers

Life extension over the design life (105hr) is required for thermal power plant in-service exposure under the conditions of highly frequent start-stop and load changes. In this artwie, three method of life evaluaflon is suggested Analytical method, Destructive test method and Non-Destructive test method. The analytical Method is based on the stress analysis and the calculation of life consumption due to fatigue and creep damage by using the operating data. The destrwctive test method is based on the evaluation of residual life by the usual creep and fatigue tests. The non-destrwctive examination is based on the measur7nent of variation in metal microstrwcture and physical properties, namely hardness, Electric resistance, X-ray diffraction and so on. This method has recently been considered an important method especialiy due to its merits such as quick evaluation and periodical monitoring.