Twenty Years of Fracture Mechanics and Flaw Evaluation Applications in the ASME Nuclear Code

The paper presents a retrospective on the development and applications of fracture mechanics-based toughness requirements and flaw evaluation methodology in Sections III and XI of the ASME Code. Section III developments range from the rules and requirements for thick section Class 1 pressure vessels to thinner section components in other Classes. Section XI applications include flaw acceptance standards and evaluation methodology for various components ranging from pressure vessels to thin section piping of carbon and austenitic steels. The experience gained in operating plant applications of these rules and procedures are also discussed.