Constraint effects on the behaviour of surface cracks in cladded reactor pressure vessels subjected to PTS transients

摘要

Crack tip stress fields of some surface crack configurations through the cladding (the stainless steel layer on the inner surface of the vessels) were investigated in two types of reactor pressure vessels subjected to severe transient conditions.The crack driving force and the crack tip constraint were evaluated along the crack front. The magnitude and distributions of the cladding residual stresses and their contributions to the crack driving force were investigated. Some issues employing the R6 method in the fracture assessment of such cracks were also discussed.