Questions and solutions on the method of remaining-life evaluation of structural materials in high-temperature power plants

This paper deals with solutions for technical questions on the remaining-life assessment of fossil fuel power plants in Japan. The difference in reliability and accuracy between rationalization of regular inspection and life extension of working plants, importance of clinical methods for damage evaluation, difficulties in the quantitative evaluation of various kinds of damage, necessity of crack- and/or cavity-totolerant assessments and standardization of allowable defect size, limitation of reliability and accuracy of present methods are discussed. A methodology based on an inverse analysis of cracks or cavities is presented as a new method of damage evaluation of materials.