Effects of weld-overlay cladding on the structural integrity of reactor pressure vessels during pressurized thermal shock

Nishikawa, Hiroyuki; Katsuyama, Jinya  ; Onizawa, Kunio 

Thermal-elastic-plastic-creep analyses based on finite element method have been performed to evaluate residual stress distribution in a RPV produced by weld-overlay cladding and PWHT. Stress intensity factors (SIFs) during PTS have also been computed based on the influence function method. The maximum value of SIF during PTS considering weld-overlay cladding is higher than that without the consideration of weld-overlay cladding. The effect of the weld-overlay cladding on the temperature margin of the structural integrity of RPVs has been evaluated. The effect of the weld-overlay cladding on the temperature margin is enough small that the effect would within the range of the margin set in the integrity assessment method.