Constraint Dependent J R Curves of a Dissimilar Metal Welded Joint for Connecting Pipe Nozzle of Nuclear Pressure Vessel

Abstract

In this paper, the JR curves of two cracks (A508 HAZ crack 2 and A508/Alloy52Mb interface crack 3) located at the weakest region in an Alloy52M dissimilar metal welded joint (DMWJ) for connecting pipenozzle of nuclear pressure vessel have been measured by using single edgenotched bend (SENB) specimens with different crack depths a/W (different constraint). Based on the modified Tstress constraint parameter د„*, the equations of constraintdependent JR curves for the crack 2 and crack 3 were obtained. The predicted JR curves using different constraint equations derived from the three pairs of crack growth amount all agree with the experimental JR curves. The results show that the modified Tstress approach for obtaining constraintdependent JR curves of homogeneous materials can also be used for the DMWJs with highly heterogeneous mechanical properties (local strength mismatches) in nuclear power plants. The use of the constraintdependent JR curves may increase the accuracy of structural integrity design and assessment for the DMWJs of nuclear pressure vessels.