Effects of wall thickness upsets at inductive pipe bends on strength

Inductive bending in piping systems is widely used in nuclear power plants. This methodology induces wall thickness upsets in compression zones and wall thickness thinning in tension zones. The authors discuss the stress distribution in pie elbows and the influence of wall thickness upsets on the material strength. Usual pipe analyses do not consider wall thickness upsets. The authors conclude the a re-evaluation is not necessary for the local stress analysis if the wall thickness upset at intrados is not more than 150% but should be performed with respect to global effects. Further conditions for a recommended re-evaluation of individual pipes are summarized.