A series of tests on small-bore Carbon steel piping specimens with bends has been performed within the Feeder Bend Testing Program. The objective of the tests was to explore the effect of global and local wall thinning on the structural behaviour of feeder pipes in CANDU® reactors. Tests involved both cyclic and monotonic bending loading together with static pressure in order to obtain information about both the ultimate load carrying capacity and the fatigue life.
The specimens were thinned locally to below the NB-3600 pressure based wall thickness within or near the bend. Results of cyclic tests are reported and discussed. For one of the tests, a fatigue crack initiation and a fatigue crack growth analysis were performed. The results have relevance as an evaluation of the conservatism of traditional piping design methods, as well as a benchmark for fitness-for-service approaches, such as flaw tolerance evaluation.
