Creep Fatigue Crack Initiation Assessment for Weldment Joint Using the Latest R5 Assessment Procedure

Boiler tube to tubeplate welds are often seen in the power generation industry. In the nuclear power industry, especially in Advanced Gas-Cooled Reactors, the welds are exposed to long term creep temperature and are subjected to fatigue cycles due to start-up and shutdown. The creep-fatigue crack initiation life assessment for the weld is required for the purposes of ensuring of safe operation and life extension. This paper presents the detailed assessment methodologies to perform a creep-fatigue crack initiation assessment using the latest R5 volume 2/3 (Issue 3 Revision 002, 2014) for the boiler superheater header tubeplate to tube Type 316 welds. The key changes of the revised R5 procedure are also outlined in the paper.