A Probabilistic evaluation model for welding residual stress distribution at piping joint in probabilistic fracture mechanics analysis

Ito, Hiroto; Katsuyama, Jinya  ; Onizawa, Kunio 

In JAEA, we have been developing probabilistic fracture mechanics (PFM) analysis methods for aged piping based on latest aging knowledge and an analytical code, PASCAL-SP. PASCAL-SP evaluates the failure probability of piping at aged welded joints under SCC and In-Service Inspection by a Monte Carlo method. We proposes a probabilistic model which can be applied to the failure probability analysis based on PFM for welded joint of piping considering the uncertainty of welding residual stress. And the probabilistic evaluation model is introduced to PASCAL-SP. A parametric PFM analysis concerning uncertainties of residual stress distribution using PASCAL-SP was performed. The PFM analysis showed that the uncertainties of residual stress distribution about heat input and welding speed largely influenced break probability. The break probability increased with increasing the uncertainties.