Assessment of the high-temperature response of structures: developments in the R5 procedure

The design and assessment of plant which operates at high temperature requires the consideration of creep effects and their interaction with fatigue. The R5 procedure has been developed within Nuclear Electric to provide a comprehensive assessment procedure for the high temperature response of structures. Damage in operating plant is often associated with welds and with defects, and R5 contains particular procedures for the assessment of structures containing such features under both creep and creep-fatigue loadings. Issue 2 of R5 has now been released and this paper briefly summarises the basic approach of R5 and highlights the most significant advances since Issue 1. Particular emphasis is placed on methods for the treatment of crack growth, and of dissimilar metal welds. (author)