Hydrogen damage in a rear riser water wall tube of a power plant

The purpose of this work is to assess a gouge defect in a pipe submitted to internal pressure. To do that a method based on failure assessment diagram and more precisely on a Modified Notch Failure Assessment Diagram (NMFAD) which has been proposed as a mesofracture approach. The safety factor has been determine under conservative conditions i.e. for a X52 pipe steel having a relatively low fracture toughness and a severe gouge defect with high aspect ratio and high constraint. In addition a mesofracture approach of the fracture toughness transferability problem has been proposed. The crack (K–T) methodology has been modifying to create the (Kρ–Tef) two parameters fracture resistance criterion.