Project of integrity assessment of flawed components with structural discontinuity (IAF). Data book for residual stress analysis in weld joint. Weld joint in shroud support (H8, H9, H10 and H11 welds)

The project of Integrity Assessment of Flawed Components with Structural Discontinuity (IAF) was entrusted to Japan Power Engineering and Inspection Corporation (JAPEIC) from Nuclear and Industrial Safety Agency (NISA) and started from FY 2001. And then, it was taken over to Japan Nuclear Energy Safety Organization (JNES) which was established in October 2003 and carried out until FY 2007. In the IAF project, weld joints between nickel based alloys and low alloy steels around penetrations in reactor vessel, safe-end of nozzles and shroud supports were selected from among components and pipe arrangements in nuclear power plants, where high residual stresses were generated due to welding and complex structure. Residual stresses around of the weld joints were estimated by finite element analysis method (FEM) with a general modeling method, then the reasonability and the conservativeness was evaluated. In addition, for postulated surface crack of stress corrosion cracking (SCC), a simple calculation method of stress intensity factor (K) required to estimate the crack growth was proposed and the effectiveness was confirmed. JNES compiled results of the IAF project into Data Books of Residual Stress Analysis of Weld Joint, and Data Book of Simplified Stress Intensity Factor Calculation for Penetration of Reactor as typical Structure Discontinuity, respectively. Data Books of Residual Stress Analysis in Weld Joint. 1. Butt Weld Joint of Small Diameter Cylinder (4B Sch40) (JNES-RE-2012-0005), 2. Dissimilar Metal Weld Joint in Safe End (One-Side Groove Joint (JNES-RE-2012-0006), 3. Dissimilar Metal Weld Joint in Safe End (Large Diameter Both-Side Groove Joint) (JNES-RE-2012-0007), 4. Weld Joint around Penetrations in Reactor Vessel (Insert Joint) (JNES-RE-2012-0008), 5. Weld Joint in Shroud Support (H8, H9, H10 and H11 Welds) (JNES-RE-2012-0009), 6. Analysis Model of Dissimilar Metal Weld Joint Applied Post Weld Heat Treatment (PWHT) (JNES-RE-2012-0010). Data Book of Simplified Stress Intensity Factor Calculation. 1. Surface Crack on ICM Housing for Penetration in Reactor Vessel (JNES-RE-2012-0011). Example FEM analysis results, measurements and comparisons of them for residual stresses are described in the above 6 volumes of Data Book of Residual Stress Analysis in Weld Joint. And these analyses were performed with material properties up to high temperature which were obtained in IAF project. It is proposed that evaluation formulas for K of simple structures like cylinder and plane can be applied to calculate K of complex structures and comparisons with FEM analyses and described as an evidence of reasonability and conservativeness. However, the analysis 1 models and conditions are described on condition of functions of specified analysis code. It is necessary to investigate references from activity reports of IAF project if another analysis code is applied. This report is described evaluations and conclusions about residual stresses around weld joint in shroud support, as follows; Residual stresses were analyzed by FEM and the results were compared with measured data of mock-up. The analysis results were roughly in accordance with the measured data, and further the analysis results were conservative on internal stresses. Parametric analyses were carried out. It was confirmed that simplified evaluation method, in which only welding heat input was taken into account, was effective when candidate was been definable and three dimensional model was effective for internal stress in legs. (author)