Residual life prediction of service exposed main steam pipe of boilers in a thermal power plant

This paper deals with residual life prediction methodology for more than 12.5 years service exposed main steam pipes of various boilers in a thermal power plant. Health assessment was made using destructive accelerated stress rupture and tensile tests at different temperatures, and some nondestructive tests. There was no evidence of localised damage in the form of surface cracks, cavitation or dents in the service exposed main steam pipes of all the boilers. So far as the remaining life at 550°C is concerned, it is possible to obtain a life of greater than 100,000 h at the hoop stress level of the service exposed pipes, provided no localised damage in the form of cracks or dents have been developed. It is recommended that a health check may be carried out after 50,000 h of service exposure at 550°C.