The project is an effort to understand behavior and predict performance of repair welds in high temperature plants. A methodology for assessing high temperature components containing repair welds is being developed on the base of a scientific foundation for understanding and predicting creep/fatigue crack behavior in repair welded components and finite element models for relating microstructure and properties of the repair weld region to the behavior of components. Various situations of repair welds and four materials (ferritic, austenitic and martensitic steels) are being studied. Sophisticated FE modeling techniques encapsulating the complexities of repair welds and a number of lab and feature tests to validate FE models are used to produce an integrated remaining life assessment methodology and guidelines for the use of crack assessment procedures. This includes relations to NDT findings and consideration of residual stresses.