Lifing of high temperature plant: deterministic and probabilistic methods

Selected application examples of life assessment by deterministic and probabilistic methods are shown for three power plant components after long term service at high operating temperatures. The case examples are made anonymous but include general features of design, operation, materials, damage evolution and in-service observations that correspond to reality. While not mutually exclusive, deterministic and probabilistic approaches carry characteristic advantages and limitations, and both can be applied in a variety of ways for component life assessment. There is a gradual trend to increasingly apply probabilistic methods for the purpose, mainly to deal in a balanced way with the factors of uncertainty, and to include the outcome to the processes of risk-based inspection and maintenance. The trend is also supported by increasing availability of tools and expertise for probabilistic and risk based methods.