applied fracture mechanics

278Applied Fracture MechanicsOnce the weight function is defined it can be implemented in a simple spreadsheet programthat can easily compute the integral for the stress intensity calculation taking into accountthe stresses evaluated in the undamaged structure by mean the FE code described in theprevious paragraph.Figure 12. Safety margin evaluation for RPV brittle ruptureThe results of the fracture mechanics analysis is a curve representing the value of the stressintensity factor in the selected scenario that is compared with the critical stress intensityfactor curve of the material obtained from the analysis of the specimens by mean the CVNtest.In Figure 12 an example of this comparison is shown. The distance between the two curvesgives the safety margin for the RPV operability.Author detailsDino A. Araneo and Francesco D’AuriaGRNSPG, San Piero a Grado Nuclear Research Group, San Piero a Grado, Pisa, Italy8. References[1] INEEL, RELAP5-3D Code Manuals, vol. I, II, IV, and V, Idaho National Engineeringand Environmental Laboratory, INEEL-EXT-98-00834, Rev. 1.1b, 1999.[2] RELAP5 MOD 3.3 Code Manual, Volume IV “Models and Correlations”, Nuclear SafetyAnalysis Division, ISL 2006.[3] W.L. Weaver, R.A. Riemke, R.J. Wagner and G.W. Johnsen. “The RELAP5 MOD3 codefor PWR safety analysis”. Proc. 4 th International Topical Meeting on Nuclear ReactorThermal-hydraulic, Karlsruhe, Germany. Vol. 2. 1991. pp. 1221-1226.