R5 and British Standards defect assessment procedures

In this paper, a basic high temperature defect assessment procedure is first described. This is common to the Nuclear Electric R5 procedure and the British Standards Document PD6539. Then the paper provides some details of the PD6539 method and the R5 procedure. The latter procedure covers a number of situations beyond the scope of the basic procedure, such as crack growth in dissimilar metal welds and creep-fatigue crack growth, and these are discussed.