Analytical Method for the Calculation of J Parameter for Surface Cracks in Piping Welds
RSE-M and RCC-MR codes provide flaw assessment methodologies and related tools for Nuclear Power Plant. AREVA, CEA and EDF developed in particular a large set of compendia for the calculation of the parameter J for various components (plates, pipes, elbows, ...) and various defect geometries. The last step of these developments deals with the weld joints : since 2004, the partners are developing a methodology to calculate the J parameter for a defect located in a weld, less conservative than usual methods. This methodology is based on the definition of an equivalent material that leads to the same J value (with same loading conditions and defect geometry) than the bi-material component. The stress-strain curve of this equivalent material is deduced from a combination of the tensile curves of the base metal and of the weld metal. The weigth coefficients applied are specifically defined for the J calculation and generalized to deal with any weld joint geometry.