A wall thinning phenomenon caused by erosion, corrosion and flow accelerated corrosion is one of critical issues that should be resolved to assure the structural integrity of nuclear piping systems. The wall thinning is occasionally detected around geometry discontinuities and its excessive amount of volume loss may reach an unanticipated rupture of a piping system. In this research, fluid effects on typical piping components are investigated and a methodology to assess the structural integrity of which has a wall-thinned part is introduced. Parametric three-dimensional fluid-structure interaction and limit load analyses are carried out and, thereby, a new analytical equation reflecting the effects of assorted fluid flow and defect geometry is developed. (C) 2008 Elsevier Ltd. All rights reserved.